ABSTRACT Infectious diseases are a health problem today and have high mortality rates with a wide diversity of potentially pathogenic microorganisms. Research that is based either on the search for new drugs from plants or on the improvement of phytotherapeutics is prominent and continues to play an important role nowadays. From this perspective, use of in silico studies to carry out investigations of new molecules potentially active for methicillin-resistant Staphylococcus aureus and Escherichia coli using an in-house database with 421 different secondary metabolites selected from the literature from Solanum genus was performed. We also realized an in vitro study with strains of S. aureus and E. coli and compared the results. Two databases from ChEMBL were selected, the first one with activity against methicillin-resistant S. aureus and another against E. coli. The compounds were classified according to the pIC50 values to generate and validate the model using a "Random Forest". The "Random Forest" prediction model for methicillin-resistant S. aureus obtained an accuracy of 81%, area under the Receiver Operating Characteristic curve of 0.885, selecting eight molecules with an active potential above 60%. The prediction model for E. coli obtained an accuracy rate of 88%, area under the Receiver Operating Characteristic curve of 0.932, selecting four molecules with potential probability above 84%. Rutin proved to be potentially active in the in silico study for S. aureus and E. coli. Microbiological tests have shown that rutin has activity only for E. coli. An interaction study with strains of S. aureus ATCC 25923, a standard strain sensitive to all antibiotics, and SAM-01, a multidrug-resistant strain, was designed. There was interaction only between rutin and oxacillin, one of the three antibiotics studied in the interaction, for the strain SAM-01, reducing the resistance of this strain.

ABSTRACT Harrisia adscendens (Gürke) Britton & Rose is a species of the family Cactaceae found in the northeastern semi-arid and popularly known as foxtail. In folk medicine, the roots of this species are used for the treatment of toothache and heartburn. The objective of this study was to perform the isolation and identification of the secondary metabolites obtained from the vegetal drug by chromatographic and spectroscopic techniques and to evaluate the antimicrobial activity of the extract. The qualitative phytochemical analysis of the extract showed suggestive results for the presence of alkaloids. Two compounds were isolated and identified: 2-methyl-9H-β-carboline-2-ion, a β-carboline alkaloid obtained for the first time as a natural product and 2',6'-dihydroxy-4'-methoxyacetophenone-2'-O-β-glucoside. In the antimicrobial tests, it was possible to observe activity against Pseudomonas aeruginosa. The results obtained by spectroscopic techniques allowed to characterize the phytochemical properties of the vegetal drug and may be useful in future studies for production of herbal medicines.

Investigou-se a qualidade microbiológica do leite in natura e na linha de produção (leite recém-pasteurizado e leite ensacado), de uma usina de beneficiamento em Campina Grande-PB. Foi pesquisada a presença de Listeria spp. e sua diversidade de espécies, os níveis de coliformes totais (CT), coliformes fecais (CF) e Escherichia coli. Analisou-se um total de 75 amostras de leite, sendo 45 de leite cru, 15 de leite recém-pasteurizado e 15 de leite ensacado. Os resultados foram reunidos em dois grupos segundo o período de monitoramento: antes e após mudanças no processo de higienização da usina. Foi evidenciada elevada contaminação nas amostras de leite cru nas duas épocas. Na primeira (março-abril/1998), todas as amostras de leite beneficiado estiveram fora dos padrões da legislação vigente para CT e CF; na segunda (maio-agosto/1998), houve acentuada redução dos níveis destas bactérias indicadoras, porém as melhorias na higienização não foram suficientes para solucionar este problema, visto que 11,1% das amostras recém-pasteurizadas estavam fora dos padrões para CT e 33,3% para CF. Das amostras ensacadas, 22,2% estavam fora dos padrões para CT e 44,4% para CF. Comparando-se os resultados de CT, CF, e E.coli nas amostras de leite recém-pasteurizado e não ensacado com as amostras de leite ensacado, foi verificado que as amostras após serem pasteurizadas e ensacadas apresentaram valores de CT e CF levemente mais elevados, sugerindo contaminação durante o processo de ensacamento ou falhas na armazenagem. Observou-se que 33 (73,3%) das amostras de leite cru e 9 (30%) das de leite pasteurizado estavam contaminadas com Listeria spp., sendo identificadas L. monocytogenes em 17 (51,5%) amostras de leite cru e em 9 (100%) de leite beneficiado (4 recém-pasteurizadas e 5 ensacadas). Em relação à diversidade de espécies, nas amostras de leite cru foram encontradas: L. monocytogenes (66,6%), L. innocua (25,3%), L. ivanovii (3,9%), L. welshimeri (2,5%) e L. grayi (1,5%). Nas amostras de leite pasteurizado isolaram-se: L. monocyogenes e L. innocua. O conjunto dos resultados evidenciou deficiências higiênico-sanitárias no leite in natura e ao longo do processo de produção, resultando em porcentagens elevadas de amostras que ultrapassaram os valores padrões de CT e CF além de apresentarem-se contaminadas por Listeria spp., com predominância de L. monocytogenes, sugerindo a existência de uma relação direta entre os altos índices de coliformes e a presença de Listeria spp.

The microbiological quality of raw and pasteurized milk was studied along its line production in a dairy factory in Paraíba State, Brazil. Listeria monocytogenes was frequent found in raw milk and the levels of total coliforms (TC), fecal coliforms (FC) and Escherichia coli, were high in the same samples. The results of 75 milk studied samples (45 raw milk, 15 recently pasteurized and 15 sacked), were distributed in two clusters, according its collected period (before and after changes in factory's hygienic process). Both raw samples groups showed high contamination. In the first period (March-April/1998), all the pasteurized milk were out of total and fecal coliforms standards. During the second period (May-August/1998), there was a significant reduction of coliforms levels, however the progress in hygienic conditions were not enough for eliminate the contamination: 11.1% of recent pasteurized milk samples and 22.2% of sacked milk samples were out of TC and also 33.3% and 44.4% recent pasteurized and sacked milk samples. Sacked milk presented more TC and FC than recent pasteurized milk, suggesting contamination after pasteurization or failure at storage. Listeria spp. was found in 33 raw milk samples (73.3%) and in 9 (30%) of pasteurized milk samples. L. monocytogenes was isolated in 17 (51.5%) raw milk samples and in 9 (100%) pasteurized milk samples (4 recent-pasteurized and 5 sacked). The Listeria spp. diversity was: L. monocytogenes (66.6%), L. innocua (25.3%), L. ivanovii (3.9%) L. welshimeri (2.5%) and L. grayi (1.5%). In the pasteurized milk was isolated only: L. monocytogenes and L. innocua. The results suggest a direct relation between high levels of coliforms and presence of Listeria spp.