Detecção de Staphylococcus aureus utilizando a técnica de REP-PCR no monitoramento da qualidade do leite de cabra Detection of Staphylococcus aureus using the REP-PCR technique to monitor goat milk quality

Este estudo foi realizado com o objetivo de aplicar a técnica de REP-PCR no monitoramento da qualidade do leite de cabra por meio da detecção de Staphylococcus aureus em amostras de mãos de ordenhador, tetos das cabras, leite, ordenhadeira e água para estabelecimento e implantação do sistema de Análise de Perigos e Pontos Críticos de Controle (APPCC). Verificaram-se vários fingerprints de todos os isolados coletados das diferentes fontes estudadas (mãos de ordenhador, tetos das cabras, leite, ordenhadeira e água). Observaram-se comportamentos muito similares das bandas, o que indica que os isolados podem ser relatados como clones epidemiológicos. As mãos do ordenhador caracterizaram-se como ponto crítico de controle, pois se destacaram como iniciador de contaminação nas amostras Staphylococcus aureus. A técnica demonstrou ser eficiente para a análise da similaridade entre indivíduos da espécie Staphylococcus aureus e, portanto, constitui ferramenta útil para investigação de falhas no manejo e na busca de controle mais eficiente para evitar ou reduzir a disseminação de microrganismos patogênicos causadores de sérias enfermidades em humanos e animais, que muitas vezes podem ser transmitidas por produtos como o leite e seus derivados.<br>The objective of the present study was to apply REP-PCR sequences in the monitoring goat milk quality, by detecting Staphylococcus aureus, in samples of from milker hands, goat teats, milk, milking machine and water, for the future establishment and implantation of the system of Hazard Analysis Critical Control Points (HACCP). Several fingerprints were verified of all the isolates collected from the different sources studied (milker hands, goat teats, milk, milking machine and water). Very similar band behaviors were observed that indicated that the isolates can be reported as epidemic clones. Milker´s hands were was characterized as a critical control point (CCP), because it stands out as an initial point of contaminationin the Staphylococcus aureus samples. The technique was shown to be efficient for the similarity analysis among individuals of the Staphylococcus aureus species, and is therefore a useful tool for investigation of management faults and consequently, in the search for more efficient control to prevent or minimize the spread of pathogenic microorganisms that cause serious illnesses in humans and animals that can be transmitted through products such as milk and its products

Diversity of Burkholderia isolates from woodland rhizosphere environments

Aims: Determination of genetic diversity among UK Burkholderia cepacia isolates from various environmental niches, principally woodland tree rhizospheres and onions. Methods and Results: Genus determination was made using polymerase chain reaction (PCR) amplification and fatty acid methyl ester profiling. Genetic diversity was investigated by repetitive sequence genetic PCR fingerprinting. Several onion isolates were similar to clinical isolates but others were diverse. Some environmental isolates were possibly synonymous with B. cepacia and B. gladioli but most from woodland rhizospheres were distinct and clustered together. The 16S rRNA genes of representatives from these clusters were PCR amplified, sequenced and phylogenetically compared with all known Burkholderia and related species. This revealed that the rhizospheric isolates had closest affinity with Burkholderia spp. with known bioremediative and biocontrol capabilities and were unrelated to taxa comprising plant or human pathogenic strains. Conclusions: All of the analyses investigated revealed that environmental and onion isolates of B. cepacia complex bacteria are genetically diverse but that woodland rhizospheric isolates are related to each other and unrelated to plant or human pathogenic strains. Significance and Impact of the Study: Woodland rhizospheric isolates of B. cepacia are potentially good candidates for use in bioremediation and biocontrol, as they appear distinct from plant or human pathogenic strains.Peer reviewe

Custo adaptativo da indução de resistência em feijoeiro mediada pela rizobactéria Bacillus cereus ou acibenzolar-S-metil: atividade de enzimas, síntese de fenóis e lignina e biomassa Fitness cost of induced resistance in bean plants by the rhizobacteria Bacillus cereus or acibenzolar-S-methyl: enzymes activities, phenol and lignin synthesis, and biomass

Plantas que utilizam recursos para defesa na ausência de pragas ou patógenos, arcarão com custos energéticos que podem refletir na sua produtividade. Assim, teve-se por objetivo avaliar os custos adaptativos da indução de resistência, antes da chegada do patógeno, em feijoeiro induzido por um indutor biótico (Bacillus cereus) e um abiótico (acibenzolar-S-metil, ASM), em 2, 3 ou 4 aplicações distribuídas ao longo do ciclo da cultura. Avaliou-se o efeito protetor contra a bactéria Xanthomonas axonopodis pv. phaseoli, além da atividade de peroxidase, quitinase, &#946;-1,3-glucanase, síntese de lignina, fenóis e crescimento com base na matéria seca. Observou-se que os indutores protegeram a cultura contra X. axonopodis pv. phaseoli com base na redução da severidade. O ASM aumentou a atividade de peroxidase, quitinase e &#946;-1,3-glucanase, enquanto que o B. cereus aumentou apenas a peroxidase. O ASM aumentou a síntese de lignina e B. cereus não, enquanto que ASM diminuiu teor de fenóis e B. cereus não. O ASM reduziu a biomassa da planta, o que não ocorreu em plantas induzidas por B. cereus. Portanto, a resistência induzida por ASM apresenta elevado custo associado, enquanto que por B. cereus apresenta baixo custo, necessitando a indução de resistência ser melhor explorada e estudada para potencializar seu uso em feijoeiro.<br>Plants that use resources to defend themselves in the absence of pests or pathogens will pay off with energy costs that can reflect in the productivity. Thus, the objective of this work was to evaluate the fitness costs of the resistance induced in bean plants, before the presence of the pathogen, by using biotic (Bacillus cereus) and abiotic (acibenzolar-S-methyl, ASM) inducers, applied 2, 3 or 4 times during the cycle of the culture. The protecting effect was evaluated against the bacterium Xanthomonas axonopodis pv. phaseoli. The activities of peroxidase, chitinase and &#946;-1,3-glucanase, lignin and phenol synthesis and plant growth were evaluated too. It was observed that the inducers protected the bean plants against X. axonopodis pv. phaseoli. The ASM increased the activity of peroxidase, chitinase and &#946;-1,3-glucanase, while B. cereus only increased peroxidase activity. Unlike B. cereus, the ASM increased lignin synthesis and decreased phenolic compound content and plant growth. Therefore, the resistance induced by ASM represents high fitness costs for bean plants, while the resistance induced by B. cereus represents low cost and its potential use can be explored