Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Mais filtros

Intervalo de ano de publicação
J Ethnopharmacol ; 265: 113248, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32805356


ETHNOPHARMACOLOGICAL RELEVANCE: Verbesina macrophylla (Cass.) S.F.Blake is a medicinal plant from South America, popularly known as "asa de peixe", "asa de peixe branco", "cambará branco" or "cambará guaçu", being used by traditional communities for its healing powers in the form of teas, infusions, liqueurs and extracts, for the treatment of bacterial and fungal infections of the urinary and respiratory tracts, such as kidney problems, bronchitis, inflammation and fever. However, none of the ethnopharmacological properties has been scientifically evaluated. AIM OF THE STUDY: Based on the ethnopharmacological use of the species, this study investigated the chemical composition, and for the first time acute toxicity, hemolytic, antimicrobial, anti-inflammatory and antipyretic activities of the essential oil from leaves of V. macrophylla. MATERIAL AND METHODS: The essential oil was obtained from the leaves by hydrodistillation (HD), being characterized by gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography coupled to flame ionization detection (GC-FID). The antimicrobial activity was evaluated by the broth microdilution technique in bacteria and fungi that cause infections of the respiratory and urinary tract, and toxicological safety regarding hemolytic activity on human red blood cells (hRBCs), and acute toxicity in mice. The anti-inflammatory activity was evaluated by the model carrageenan-induced peritonitis with quantification of the levels of TNF-α and IL-1ß in the intraperitoneal fluid, and ear edema induced by croton oil. The antipyretic activity evaluated in mice with pyrexia induced by yeast. RESULTS: The extraction of essential oil by hydrodistillation (HD) showed a yield of 0.33 ±â€¯0.04%, with its composition constituted mainly by sesquiterpenes of hydrocarbons (94.00%). The essential oil demonstrated antibacterial and antifungal activity, with a low rate of hemolysis in human red blood cells (hRBCs) and no clinical signs of toxicity were observed in animals after acute treatment, which suggested that the LD50 is greater than 5000 mg/kg; p.o. The essential oil demonstrated anti-inflammatory activity reducing levels of pro-inflammatory cytokines TNF-α (38.83%, 72.42% and 73.52%) and IL-1ß (37.70%, 75.92% and 87.71%), and ear edema by 49.53%, 85.04% and 94.39% at concentrations of 4, 40 and 400 mg/kg, respectively. The antipyretic activity presented by the essential oil is statistically similar to dipyrone. CONCLUSION: The set of results obtained, validates the main activities attributed to the traditional use of Verbesina macrophylla (Cass.) S.F.Blake. These data add industrial value to the species, considering that the antimicrobial, anti-inflammatory and antipyretic activities present results similar to the drugs already used also presenting safety. The results suggest that essential oil from V. macrophylla may be used by industry for the development of drugs with natural antimicrobial, anti-inflammatory and antipyretic effect.

J Ethnopharmacol ; 247: 112265, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31580941


ETHNOPHARMACOLOGICAL RELEVANCE: Hymenaea cangaceira Pinto, Mansano & Azevedo (Fabaceae) is a Brazilian medicinal plant widely known as "Jatobá". In folk medicine, it is used to treat infections, respiratory problems, rheumatism, antitumoral, inflammation and pain, however, no activity has been scientifically validated. AIM OF THE STUDY: This study investigated chemical composition of essential oil from Hymenaea cangaceira (EOHc), antimicrobial, antinociceptive and antioxidant activities besides protection against DNA damage and hemolysis. MATERIAL AND METHODS: The essential oil was obtained by hydrodistillation, and characterized by GC-MS and GC-FID. The evaluation of antimicrobial activity was performed by microdilution method. The evaluation of the antioxidant activity was performed using the radicals DPPH, ABTS, O2- and OH-, and the protection of DNA damage using plasmid pBR322. Different experimental models were used to evaluate the antinociceptive effect (acetic acid and formalin), and evaluate the mechanisms of action involved with pharmacological antagonists (naloxone, atropine and gibenclamide) in mice. The essential oil was evaluated for hemolysis on human erythrocytes. RESULTS: The extraction of EOHc showed a yield of 0.18% on a dry basis, presenting high content of hydrocarbon sesquiterpenes (79.04%), high antioxidant activity and protect DNA from damage, besides presenting antifungal and antibacterial activity against Gram-positive and Gram-negative bacteria in vitro. It was found that the essential oil had no acute toxicity in mice up to 5000 mg/kg oral administration (o.a.), in addition to no hemolysis on human erythrocytes. The reduction of antinociceptive activity was 75%, with the opioid system as the mechanism of action. CONCLUSION: Our results validate the main activities by the traditional use attributed to H. cangaceira for antimicrobial and analgesic activity. In addition, the oil has a potent antioxidant activity, protecting the body against oxidative stress damage, adding new value to an endemic species not known to the industry.

Analgésicos/farmacologia , Antibacterianos/farmacologia , Antioxidantes/farmacologia , Hymenaea/química , Óleos Voláteis/farmacologia , Óleos Vegetais/farmacologia , Ácido Acético/toxicidade , Analgésicos/química , Analgésicos/isolamento & purificação , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antioxidantes/química , Antioxidantes/isolamento & purificação , Brasil , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Etanol/química , Etnofarmacologia , Formaldeído/toxicidade , Humanos , Medicina Tradicional/métodos , Camundongos , Testes de Sensibilidade Microbiana , Nociceptividade/efeitos dos fármacos , Óleos Voláteis/química , Óleos Voláteis/uso terapêutico , Dor/induzido quimicamente , Dor/diagnóstico , Dor/tratamento farmacológico , Medição da Dor , Óleos Vegetais/química , Óleos Vegetais/isolamento & purificação , Testes de Toxicidade Aguda
J Microbiol Biotechnol ; 28(7): 1078-1085, 2018 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-29926709


A salt-tolerant cellulase secreted by a marine Bacillus sp. SR22 strain with wide resistance to temperature and pH was purified and characterized. Its approximate mass was 37 kDa. The endoglucanase, named as Bc22Cel, was purified by ammonium sulfate precipitation, gel filtration chromatography, and extraction from the gel after non-reducing sodium dodecyl sufate-polyacrylamide gel electrophoresis. The optimal pH value and temperature of Bc22Cel were 6.5 and 60°C, respectively. The purified Bc22Cel showed a considerable halophilic property, being able to maintain more than 70% of residual activity even when pre-incubated with 1.5 M NaCl for 1 h. Kinetic analysis of the purified enzyme showed the Km and Vmax to be 0.704 mg/ml and 29.85 µmol·ml-1·min-1, respectively. Taken together, the present data indicate Bc22Cel as a potential and useful candidate for industrial applications, such as the bioconversion of sugarcane bagasse to its derivatives.

Bacillus/enzimologia , Proteínas de Bactérias/metabolismo , Celulase/química , Celulase/isolamento & purificação , Água do Mar/microbiologia , Bacillus/genética , Bacillus/isolamento & purificação , Bacillus/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Brasil , Celulase/classificação , Celulase/efeitos dos fármacos , Celulose/metabolismo , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Microbiologia Industrial , Cinética , Peso Molecular , Filogenia , RNA Ribossômico 16S/genética , Saccharum/metabolismo , Cloreto de Sódio/farmacologia , Especificidade por Substrato , Temperatura
Rev. biol. trop ; 65(3): 890-899, Jul.-Sep. 2017. tab, ilus
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-897590


AbstractCyanobacteria are widely distributed in terrestrial, freshwater and marine environments, and over the past decades have been recognized as a powerful source of bioactive compounds. In this study, some cyanobacterial strains were isolated from samples of seawater, brackish water and tissue of reef benthic invertebrates (zoanthid Protopalythoa variabilis, the sponges Cynachrella sp. and Haliclona sp., the coral Siderastrea stellata, and ascidians), collected at the states of Paraíba and Rio Grande do Norte (Northeast of Brazil), during the period between July 2010 and February 2014. After standard isolation methods, the cultivation of the strains was carried out in acclimatized culture chamber (25 °C) under constant aeration, for 15 days at 12-hour photoperiod, using Conway and BG11 media made with filtered seawater. The cyanobacterial cells were analysed for the microcystin production by the ELISA technique and their ethanolic and methanolic extracts for the antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa by the agar well diffusion method. The detection of the mcyB gene, one of the genes related to the microcystin synthesis, was done by the Polymerase Chain Reaction (PCR) technique. The majority of the eighteen cyanobacterial strains belonged to Synechococcaceae Family. The genera of Synechocystis, Synechococcus and Romeria were represented by ten, six and two strains, respectively. The production of microcystins was observed in five strains belonging to the genus Synechocystis. The presence of mcyB gene was detected in 12 strains of cyanobacteria: Synechocystis (three strains), Synechococcus (six strains) and Romeria (two strains). Only one strain (Synechocystis aquatilis) showed both the microcystin production and the mcyB gene presence. The antibacterial activity was observed for one strain of Romeria gracilis, one strain of Synechocystis aquatilis and two strains of Synechococcus sp. The ethanolic extracts of R. gracilis strain and two Synechococcus spp. strains inhibited the growth of P. aeruginosa. Among methanolic extracts of cyanobacteria, only one strain of S. aquatilis showed activity against S. aureus, and one R. gracilis strain against P. aeruginosa. Some cyanobacterial strains studied were positive for the microcystin production and antibacterial activity against pathogenic bacteria S. aureus and P. aeuruginosa, and may be further explored for additional biotechnological applications. Rev. Biol. Trop. 65 (3): 890-899. Epub 2017 September 01.

ResumenLas cianobacterias se encuentran ampliamente distribuidas en ecosistemas terrestres, de agua dulce y marinos, y en las últimas décadas han sido reconocidas como una poderosa fuente de compuestos bioactivos. En este estudio, las cepas de cianobacterias fueron aisladas a partir de agua de mar, agua salobre y muestras de tejidos de invertebrados bentónicos de arrecifes (zoanthid Protopalythoa variabilis, las esponjas Cynachrella sp. y Haliclona sp., el coral Siderastrea stellata y ascidias) recogidas en los estados de Paraíba y Rio Grande do Norte, en el noreste de Brasil, en el período comprendido entre julio 2010 y febrero 2014. La mayoría de las dieciocho cepas de cianobacterias pertenecían a la Familia Synechococcaceae. Los géneros: Synechocystis, Synechococcus y Romeria estuvieron representados por diez, seis y dos cepas, respectivamente. Las cepas fueron analizadas para la producción de microcistina por ELISA y para la actividad antibacteriana contra Staphylococcus aureus y Pseudomonas aeruginosa por el método de difusión en agar. La detección del gen mcyB, uno de los genes relacionados con la síntesis de microcistina, se realizó mediante la técnica de reacción en cadena de la polimerasa (PCR). El cultivo de las cepas se realizó en cámara de cultivo aclimatada (25 ° C) bajo aireación constante durante 15 días con un fotoperíodo de 12 horas utilizando los medios Conway y BG11 elaborados con agua de mar filtrada. Se observó la producción de microcistina en cinco cepas pertenecientes al género Synechocystis. La presencia del gen mcyB fue detectada en doce cepas de cianobactérias: Synechocystis (tres cepas), Synechococcus (seis cepas) y Romeria (dos cepas). Sólo una cepa (Synechocystis aquatilis) mostró tanto la producción de microcistina como la presencia del gen mcyB. Se observó la actividad antibacteriana de una cepa de Romeria gracilis, de una cepa de Synechocystis aquatilis y dos cepas de Synechococcus sp. Los extractos etanólicos de las cepas de R. gracilis y Synechococcus sp. inhibieron el crecimiento de P. aeruginosa. Entre los extractos metanólicos de cianobacterias solamente S. aquatilis mostró actividad contra S. aureus y R. gracilis contra P. aeruginosa. Varias cepas de cianobacterias estudiadas en este trabajo fueron positivas para la producción de microcistina y actividad antibacteriana frente a bacterias patógenas de S. aureus y P. aeuruginosa, y pueden ser explotadas para aplicaciones biotecnológicas.

Biotechnol Prog ; 32(2): 262-70, 2016 03.
Artigo em Inglês | MEDLINE | ID: mdl-26588432


Biosurfactants are microbial secondary metabolites. The most studied are rhamnolipids, which decrease the surface tension and have emulsifying capacity. In this study, the production of biosurfactants, with emphasis on rhamnolipids, and diesel oil degradation by 18 strains of bacteria isolated from waste landfill soil contaminated by petroleum was analyzed. Among the studied bacteria, gram-positive endospore forming rods (39%), gram positive rods without endospores (17%), and gram-negative rods (44%) were found. The following methods were used to test for biosurfactant production: oil spreading, emulsification, and hemolytic activity. All strains showed the ability to disperse the diesel oil, while 77% and 44% of the strains showed hemolysis and emulsification of diesel oil, respectively. Rhamnolipids production was observed in four strains that were classified on the basis of the 16S rRNA sequences as Pseudomonas aeruginosa. Only those strains showed the rhlAB gene involved in rhamnolipids synthesis, and antibacterial activity against Escherichia coli, P. aeruginosa, Staphylococcus aureus, Bacillus cereus, Erwinia carotovora, and Ralstonia solanacearum. The highest production of rhamnolipids was 565.7 mg/L observed in mineral medium containing olive oil (pH 8). With regard to the capacity to degrade diesel oil, it was observed that 7 strains were positive in reduction of the dye 2,6-dichlorophenolindophenol (2,6-DCPIP) while 16 had the gene alkane mono-oxygenase (alkB), and the producers of rhamnolipids were positive in both tests. Several bacterial strains have shown high potential to be explored further for bioremediation purposes due to their simultaneous ability to emulsify, disperse, and degrade diesel oil. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:262-270, 2016.

Bactérias/metabolismo , Óleos Combustíveis/análise , Glicolipídeos/biossíntese , Petróleo/metabolismo , Poluentes do Solo/metabolismo , Biodegradação Ambiental , Óleos Combustíveis/microbiologia , Glicolipídeos/química , Glicolipídeos/isolamento & purificação , Petróleo/microbiologia , Poluentes do Solo/química
Braz. arch. biol. technol ; 53(5): 1067-1072, Sept.-Oct. 2010. ilus, tab
Artigo em Inglês | LILACS-Express | LILACS | ID: lil-564082


Proteolytic activity and cell biomass of thermophilic Bacillus sp. strain were evaluated at various levels of initial pH and temperature by applying response surface methodology. The mineral medium containing yeast extract (0.01 percent) and starch (1 percent) was used throughout the experiment. The results of statistical analysis revealed the polynomial model with high coefficient of determination (R² = 0.8) for the biomass and total proteolytic activity of the strain studied. This model showed a satisfactory adjustment of the statistic model with the experimental data. The p values showed that the temperature and pH had significant effect on biomass and proteolytic activity (P<0.05) of strain tested. The highest proteolytic activity (2.333 U/ml/h) of the Bacillus sp. was predicted at 41º C and pH 4.8. The high biomass values were observed at broad range of temperature and pH.

Atividade proteolítica total e biomassa de uma linhagem de Bacillus sp. termofílico foram analisados em vários níveis de pH inicial e temperatura utilizando a metodologia de superfície de resposta. O meio mineral com extrato de levedura (0.01 por cento) e amido (1 por cento) foi utilizado no experimento. Os resultados de análise estatística da metodologia de resposta de superfície definiram um modelo polinomial para a biomassa e atividade proteolítica da linhagem de Bacillus sp. com alto coeficiente de determinação (R² = 0.8), mostrando um ajuste satisfatório do modelo estatístico obtido com os dados experimentais. Os valores de p mostraram que a temperatura e pH tiveram efeito significante em biomassa e atividade total (P <0.05) da linhagem testada. A atividade proteolítica mais alta (2.368 U/ml/h) da linhagem de Bacilus sp. foi prevista pelas curvas de superfície de resposta em temperatura a 41º C e pH igual a 4.8. Os valores de biomassa altos foram previstos para ampla faixa de temperatura e pH.

Braz. arch. biol. technol ; 53(1): 227-234, Jan.-Feb. 2010. tab, ilus
Artigo em Inglês | LILACS-Express | LILACS | ID: lil-543216


Study on mangrove water and sediment of Paraiba do Norte river (Northeastern Brazil) and crabmeat of Ucides cordatus was carried to investigate the relation between the abundance of bacteria in the mangrove habitat and in the crabmeat. Simultaneous collection of samples of water, sediment and crabs (U. cordatus) was done during the rainy and dry seasons at two areas of mangroves that differed in influence of tide and sewage discharge. The numbers of total heterotrophic bacteria in the mangrove water were between 0.04 and 6 log CFU 100mL-1, and in the sediment between 5 and 6 log CFU g-1. The location closer to waste discharge showed higher incidence of total heterotrophic bacteria, coliforms, Staphylococcus aureus and Salmonella spp. The counts of total heterotrophic bacteria in the crabmeat varied from 1.3 to 4.4 log CFU g-1, and did not differ significantly between the locations analysed. No crabmeat sample showed the presence of coliforms, S. aureus and Salmonella spp.

O estudo sobre água e sedimento do mangue do rio Paraíba do Norte (Nordeste do Brasil) e carne de caranguejo-uçá (Ucides cordatus) foi conduzido para investigar a relação entre a abundância de bactérias heterotróficas totais e patogênicas no ambiente e na carne de caranguejo. As amostras de água, sedimento e caranguejos U. cordatus foram coletadas simultaneamente em duas áreas do manguezal que diferiam em influencia da maré e do esgoto lançado no mangue. O número de bactérias heterotróficas totais nas amostras de água do mangue variaram de 0,04 a 6 log UFC 100mL-1, e no sedimento de 5 a 6 log UFC g-1. Em local mais próximo a desembocadura do esgoto evidenciou-se maior incidência de bactérias heterotróficas totais, coliformes, Staphylococcus aureus e Salmonella spp. As contagens de bactérias totais nas amostras da carne de caranguejo variaram de 1,3 a 4,4 log UFC g-1, não diferindo estatisticamente entre as áreas estudadas. Nenhuma amostra da carne de caranguejo apresentou coliformes, S. aureus e Salmonella spp.

Hig. aliment ; 21(154): 65-71, set. 2007. tab
Artigo em Português | LILACS | ID: lil-523200


O objetivo deste estudo foi investigar a qualidade microbiológica da carne de caranguejo-uçá (Ucides cordatus), comercializada nos mercados centrais das cidades de João Pessoa e Cabedelo – PB. A carne de caranguejo apresentou altos índices de contaminação com bactérias totais, coliformes e bactérias patogênicas. As amostras da carne de caranguejo do mercado central de João Pessoa apresentaram valores para bactérias totais mesofílicas (BTM) e psicrofílicas (BTP) bastante elevados, com médias equivalentes a 2,1 x10 e 7,1x10 UFC/g, respectivamente. As contagens de BTM e BTP das amostras da feira de Cabedelo foram igualmente elevadas, com médias de 1,8 x 10 UFC/g, respectivamente. (...) Os dados obtidos indicam baixa qualidade microbiológica da carne de caranguejo comercializada nas feiras-livres, e sugerem a necessidade de monitoramento microbiológico desse produto, bem como orientação aos catadores e manipuladores ao longo de toda cadeia de processamento da carne de caranguejo, para que adotem os cuidados higiênico-sanitários necessários, evitando, assim a elevada contaminação bacteriana do produto.

Animais , Braquiúros/microbiologia , Coliformes , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Frutos do Mar , Salmonella/isolamento & purificação , Staphylococcus aureus/isolamento & purificação , Brasil , Manipulação de Alimentos
Braz. j. microbiol ; 38(1): 135-141, Jan.-Mar. 2007. tab, graf
Artigo em Inglês | LILACS | ID: lil-449383


The dynamics of mesophilic and thermophilic bacterial population was studied in the bulk soil and rhizosphere of the grass Aristida adscensionis L. in a caatinga of the semi-arid Brazilian Northeast. Mesophilic heterotrophic bacteria, sporeforming bacteria and actinomycetes were significantly more abundant than thermophiles, and their counts were 10(6) - 10(7) CFU g-1 dry soil, showing weak fluctuations over the one-year study period. Thermophiles were below 10(6) CFU g-1 dry soil and, in general, demonstrated stronger fluctuations over the studied period. Among them, thermophilic actinomycetes showed the greatest decline during the dry season. No significant differences in microbial number were observed between bulk and rhizosphere soil. Mesophilic bacteria were represented mainly by Gram positive, filamentous organisms (actinomycetes) and by Gram positive, endospore-forming, rod-shaped organisms. All isolates of thermophilic bacteria were Gram positive, endospore-forming rods. Most of mesophilic isolates produced amylases and proteases, and 38 percent of isolates produced all studied extracellular enzymes: amylases, proteases, cellulases and chitinases. Among thermophilic bacteria, all isolates showed proteolytic activity and 77 percent produced amylases, but no one produced cellulases or chitinases.

A dinâmica das populações bacterianas meso e termofílicas foi estudada no solo sem raízes e rizosférico associado à gramínea Aristida adscensionis L. na caatinga da zona semi árida do nordeste brasileiro. As bactérias totais heterotróficas, as bactérias esporuladoras e actinomicetos mesofílicos foram significativamente mais abundantes que os termofílicos, suas contagens variando na ordem de 10(6) - 10(7) UFC g-1 de solo seco, apresentando flutuações discretas ao longo de um período de um ano. Microrganismos termófilos foram encontrados numa ordem de 10(6) UFC g-1 de solo seco e demonstraram, em geral, flutuações mais evidentes durante o mesmo período de estudo. Entre os termófilos, os actinomicetos apresentaram um maior declínio durante a estação seca. Nenhuma diferença significativa no número de microrganismos foi observada entre o solo rizosférico e o solo não rizosférico. As bactérias mesofílicas mais observadas foram as filamentosas Gram positivas (actinomicetos) e os bastonetes esporulantes Gram positivos. Todos os isolados termofílicos foram bactérias esporuladoras Gram positivas em forma de bacilo. A maioria dos isolados mesofílicos produziu amilases e proteases, enquanto que 38 por cento das linhagens produziram todas as enzimas extracelulares estudadas: amilases, proteases, celulases e quitinases. Entre as bactérias termofílicas, todos os isolados apresentaram atividade proteolítica e 77 por cento produziram amilases, mas nenhum produziu quitinases ou celulases.

Actinobacteria/isolamento & purificação , Bactérias Gram-Positivas/isolamento & purificação , Ensaios Enzimáticos Clínicos , Ativação Enzimática , Técnicas In Vitro , Zona Árida , Métodos , Dinâmica Populacional , Amostragem
Braz. j. microbiol ; 36(2): 151-156, Apr.-June 2005. tab, graf
Artigo em Inglês | LILACS | ID: lil-421719


O objetivo deste estudo foi avaliar o potencial de inibicão de nisina e o pH elevado em relacão à multiplicacão de Staphylococcus aureus e Salmonella sp. em culturas puras e inoculadas na carne de caranguejo-ucá. Em culturas puras, a multiplicacão de S. aureus foi fortemente inibida por nisina e a de Salmonella sp. por nisina-EDTA (20 mM). A multiplicacão de S. aureus foi inibida até 8h de incubacão, enquanto que a de Salmonella sp. foi inibida durante todo o experimento (24h). O pH elevado (tampão NaHCO3-NaOH, pH 10 e 11) mostrou-se efetivo na inibicão da multiplicacão de S. aureus e Salmonella sp. Nisina e o pH elevado aplicados na carne contaminada não apresentaram o mesmo efeito. A nisina não mostrou eficiência na inibicão dos patógenos quando inoculados na carne de caranguejo, enquanto que o tampão em pH 10 demonstrou inibicão significante sobre a multiplicacão de Salmonella sp. Estes resultados sugerem que o pH elevado apresenta um potencial como agente antibacteriano, podendo ser útil na preservacão química da carne de caranguejo.

Braquiúros , Técnicas In Vitro , Nisina , Salmonella , Infecções por Salmonella , Infecções Estafilocócicas , Staphylococcus aureus , Concentração de Íons de Hidrogênio , Métodos , Amostragem