Aceite esencial de Arazá (Eugenia stipitata McVaugh) con actividad antibacteriana / Essential oil of Arazá (Eugenia stipitata McVaugh) with antibacterial activity

Introducción: El Perú es uno de los países con mayor biodiversidad en especies botánicas, algunas con propiedades medicinales conocidas. Objetivo: Determinar el efecto antibacteriano del aceite esencial de las hojas de Eugenia stipitata McVaugh frente a Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 y Salmonella enterica sv Enteritidis ATCC 13076. Métodos: Estudio de tipo básico con enfoque cuantitativo y experimental. Las plantas provienen del distrito de Belén, ciudad de Iquitos, Departamento de Loreto. La técnica para la extracción del aceite esencial fue la de arrastre de vapor y la técnica microbiológica para determinar el efecto antimicrobiano la de Kirby Bauer. Se trabajaron las muestras en 4 concentraciones 100, 75, 50 y un 25 por ciento; un control negativo solo con dimetilsulfóxido, se utilizaron 5 repeticiones por cada muestra. Resultados: La muestra a concentración al 100 por ciento tuvo actividad antibacteriana contra Staphylococcus aureus. La actividad del ensayo frente a Escherichia coli demostró ser efectiva en todas las muestras, sin embargo, se observó que los halos de inhibición de mayor diámetro se manifestaron en las muestras al 100 por ciento y 75 por ciento. Además, se evidenció actividad antibacteriana a concentraciones del 100 por ciento, 75 por ciento y un 50 por ciento frente a Salmonella enterica sv Enteritidis. Conclusiones: El aceite esencial de las hojas de Eugenia stipitata McVaugh presenta efecto antibacteriano frente a Staphylococcus aureus, Escherichia coli y Salmonella enterica sv Enteritidis(AU)

Introduction: Peru is one of the countries with the greatest biodiversity in botanical species, some with known medicinal properties. Objective: To determine the antibacterial effect of the essential oil of Eugenia stipitata McVaugh leaves against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Salmonella enterica sv Enteritidis ATCC 13076. Methods: Basic study with a quantitative and experimental approach. Plants came from the district of Belén, city of Iquitos, Department of Loreto. The technique for the extraction of the essential oil was steam dragging and the microbiological technique to determine the antimicrobial effect was Kirby Bauer's technique. The samples were worked in 4 concentrations 100, 75, 50 and 25 percent and a negative control only with dimethyl sulfoxide, using 5 replicates for each sample. Results: The sample at 100 percent concentration had antibacterial activity against Staphylococcus aureus. The activity of the assay against Escherichia coli proved to be effective in all the samples, however, it was observed that the inhibition halos of greater diameter were manifested in the samples at 100 percent and 75 percent. In addition, antibacterial activity was evidenced at concentrations of 100 percent, 75 percent and 50 percent against Salmonella enterica sv Enteritidis. Conclusions: The essential oil of Eugenia stipitata McVaugh leaves has an antibacterial effect against Staphylococcus aureus, Escherichia coli and Salmonella enterica sv Enteritidis(AU)

Effect of dietary supplementation of bacteriophage on performance, egg quality and caecal bacterial populations in laying hens.

1. Bacteriophages (BP) have gained increasing attention as a treatment of bacterial infection for animals. However, the data pertaining to dietary application of BP for laying hens have been limited. 2. This study aimed to investigate the effect of dietary BP on laying performance, egg quality and caecal bacterial populations in laying hens. 3. The dietary BP used in this experiment was a mixture of individual BP targeting Salmonella gallinarum, Salmonella pullorum, Salmonella typhimurium, Salmonella enteritidis, Salmonella derby and Staphylococcus aureus. 4. A total of 360 Hy-Line Brown laying hens of 32 weeks of age were allotted to one of three dietary treatments with 6 replicates in a completely randomised design. The basal diet was prepared, and 0.4 or 0.8 g/kg BP mixture was supplemented to the basal diet. Diets were fed to hens for 8 weeks. 5. Laying performance and egg quality were not affected by dietary treatments. As inclusion levels of BP mixture in diets were increased, the DNA copy numbers for Salmonella spp. in the caecal contents decreased linearly, whereas the DNA copy numbers for Escherichia coli in the caecal contents increased linearly. 6. Results indicate that dietary supplementation of BP mixture decreases the target Salmonella spp. populations but increases Escherichia coli populations in the gastrointestinal tract of laying hens with little impact on laying performance and egg quality.

wksl3, a New biocontrol agent for Salmonella enterica serovars enteritidis and typhimurium in foods: characterization, application, sequence analysis, and oral acute toxicity study.

Of the Salmonella enterica serovars, S. Enteritidis and S. Typhimurium are responsible for most of the Salmonella outbreaks implicated in the consumption of contaminated foods in the Republic of Korea. Because of the widespread occurrence of antimicrobial-resistant Salmonella in foods and food processing environments, bacteriophages have recently surfaced as an alternative biocontrol tool. In this study, we isolated a virulent bacteriophage (wksl3) that could specifically infect S. Enteritidis, S. Typhimurium, and several additional serovars. Transmission electron microscopy revealed that phage wksl3 belongs to the family Siphoviridae. Complete genome sequence analysis and bioinformatic analysis revealed that the DNA of phage wksl3 is composed of 42,766 bp with 64 open reading frames. Since it does not encode any phage lysogeny factors, toxins, pathogen-related genes, or food-borne allergens, phage wksl3 may be considered a virulent phage with no side effects. Analysis of genetic similarities between phage wksl3 and four of its relatives (SS3e, vB_SenS-Ent1, SE2, and SETP3) allowed wksl3 to be categorized as a SETP3-like phage. A single-dose test of oral toxicity with BALB/c mice resulted in no abnormal clinical observations. Moreover, phage application to chicken skin at 8°C resulted in an about 2.5-log reduction in the number of Salmonella bacteria during the test period. The strong, stable lytic activity, the significant reduction of the number of S. Enteritidis bacteria after application to food, and the lack of clinical symptoms of this phage suggest that wksl3 may be a useful agent for the protection of foods against S. Enteritidis and S. Typhimurium contamination.

Significance of the bacteriophage treatment schedule in reducing Salmonella colonization of poultry.

Salmonella remains the major cause of food-borne diseases worldwide, with chickens known to be the main reservoir for this zoonotic pathogen. Among the many approaches to reducing Salmonella colonization of broilers, bacteriophage offers several advantages. In this study, three bacteriophages (UAB_Phi20, UAB_Phi78, and UAB_Phi87) obtained from our collection that exhibited a broad host range against Salmonella enterica serovar Enteritidis and Salmonella enterica serovar Typhimurium were characterized with respect to morphology, genome size, and restriction patterns. A cocktail composed of the three bacteriophages was more effective in promoting the lysis of S. Enteritidis and S. Typhimurium cultures than any of the three bacteriophages alone. In addition, the cocktail was able to lyse the Salmonella enterica serovars Virchow, Hadar, and Infantis. The effectiveness of the bacteriophage cocktail in reducing the concentration of S. Typhimurium was tested in two animal models using different treatment schedules. In the mouse model, 50% survival was obtained when the cocktail was administered simultaneously with bacterial infection and again at 6, 24, and 30 h postinfection. Likewise, in the White Leghorn chicken specific-pathogen-free (SPF) model, the best results, defined as a reduction of Salmonella concentration in the chicken cecum, were obtained when the bacteriophage cocktail was administered 1 day before or just after bacterial infection and then again on different days postinfection. Our results show that frequent treatment of the chickens with bacteriophage, and especially prior to colonization of the intestinal tract by Salmonella, is required to achieve effective bacterial reduction over time.

Salmonellosis outbreak due to Salmonella enteritidis phage type 14b resistant to nalidixic acid, Austria, September 2010.

We report on a salmonellosis-outbreak due to Salmonella Enteritidis phage type 14b resistant to nalidixic acid (S. Enteritidis PT14b Nx) among residents and employees of a student residence in Austria, September 2010. The outbreak was described and analysed by a retrospective cohort study, and microbiological environmental investigations were conducted to identify the outbreak source(s) and the reservoir of the outbreak strain. A total of 66 persons fulfilled the outbreak case definition including 14 laboratory-confirmed cases. Food specific cohort-analyses by day revealed that consumption of potato salad (RR: 1.65, 95%CI: 1.35­2.01, p=0.001) and a cheese-sausage cold plate (RR: 2.24, 95%CI: 1.29­3.88, p=0.002) on 14 September was associated with being an outbreak case. We hypothesised that cross-contamination with S. Enteritidis PT14b Nx positive eggs had occurred during preparation of the potato salad and cold plate as a result of preparing in parallel egg-containing breaded cutlets on 14 September. A traced laying hen holding in eastern Austria was identified as the sole source of the consumable eggs in the student residence. By applying the legally mandated sampling method for epidemiological-related laying hen farms (one pooled dust sample à 150g, two paired boot swabs cultured separately), the outbreak strain could not be detected. Our findings, that legally required sampling methods for laying hen farms failed to detect the causative pathogen in a laying hen holding, despite an epidemiological link, underline the request stated by the European Food Safety Authority Panel on Biological Hazards for a more sensitive sampling plan in epidemiologically-associated laying hen flocks.