Deleterious impact of a virulent bacteriophage on survival and biocontrol activity of Pseudomonas fluorescens strain CHAO in natural soil.

Many biotic and abiotic factors affect the persistence and activity of beneficial pseudomonads introduced into soil to suppress plant diseases. One such factor may be the presence of virulent bacteriophages that decimate the population of the introduced bacteria, thereby reducing their beneficial effect. We have isolated a lytic bacteriophage (phi)GP100) that specifically infects the biocontrol bacterium Pseudomonas fluorescens CHA0 and some closely related Pseudomonas strains. phiGP100 was found to be a double-stranded-DNA phage with an icosahedral head, a stubby tail, and a genome size of approximately 50 kb. Replication of phiGP100 was negatively affected at temperatures higher than 25 degrees C. phiGP100 had a negative impact on the population size and the biocontrol activity of P. fluorescens strain CHA0-Rif (a rifampicin-resistant variant of CHA0) in natural soil microcosms. In the presence of phiGP100, the population size of strain CHA0-Rif in soil and on cucumber roots was reduced more than 100-fold. As a consequence, the bacterium's capacity to protect cucumber against a root disease caused by the pathogenic oomycete Pythium ultimum was entirely abolished. In contrast, the phage affected neither root colonization and nor the disease suppressive effect of a phiDGP100-resistant variant of strain CHA0-Rif. To our knowledge, this study is the first to illustrate the potential of phages to impair biocontrol performance of beneficial bacteria released into the natural soil environment.

Postmortem angiography using femoral cannulation and postmortem microbiology.

Despite the undeniable advantages of postmortem angiography, numerous questions have arisen concerning the influence that the injected contrast media may exercise on biological fluids and tissues collected for toxicological and biochemical investigations. Moreover, cardiac blood for microbiological investigations cannot be obtained post-angiography. In this study, we examined whether the peripheral blood collected prior to postmortem angiography, using percutaneous access to femoral vessels after skin surface disinfection, could be suitable for microbiological investigations when postmortem angiography with femoral vessel cannulation is also performed. A total of 66 cases were included in the study and were divided into two subgroups (angiography and bacteriology group, 33 cases and control group, 33 cases). Autopsies, histology, toxicology, bacteriology, and biochemical investigations (procalcitonin, C-reactive protein, interleukin-6, and soluble triggering receptors expressed on myeloid cells type 1) were performed in all cases. No statistically significant differences between the two groups were noted, and identified category distribution (death unrelated to infection, true infection, false positive, and undetermined) was rather similar in both studied populations. These preliminary results suggest that postmortem angiography using a femoral approach does not constitute an impediment to the collection of peripheral blood for microbiology and vice versa. Moreover, the use of femoral blood for microbiology does not lead to an increased risk of doubtful results.

Momentum dependence of the phi-meson nuclear transparency

The production of φ mesons in proton collisions with C, Cu, Ag, and Au targets has been studied via the φ → K + K − decay at an incident beam energy of 2.83 GeV using the ANKE detector system at COSY. For the first time, the momentum dependence of the nuclear transparency ratio, the in-medium φ width, and the differential cross section for φ -meson production at forward angles have been determined for these targets over the momentum range of 0.6-1.6 GeV /c. There are indications of a significant momentum dependence in the value of the extracted φ width, which corresponds to an effective φN absorption cross section in the range of 14-21 mb.

A descriptive study on the surgery and the microbiology of Gustilo type III fractures in an university hospital in Switzerland.

OBJECTIVE: To describe the epidemiology, the surgical treatment, the microbiology, the antibiotic prophylaxis and the outcome of patients with the most severe type of open fractures. METHODS: Retrospective chart reviews of patients with Gustilo type III open fracture admitted to an university hospital in Switzerland between January 2007 and December 2011. The patient's and fracture's characteristics, surgery, antibiotic prophylaxis, and microbiology findings at the initial and at the revision surgery were described. RESULTS: Thirty patients were included (83% male, mean age 41 years). More than half of the patients had polytrauma. In all patients, debridement and stabilization surgery (70% using external fixation) were performed at admission. Soft tissue reconstruction was performed in 87% and in 23% immediate bone graft was performed. Antibiotic prophylaxis were given in all patients for a median duration of 9 days (60% received amoxicillin/clavulanic acid). Positive bacterial culture was found in 53% of the patients at initial surgery and in 88% at revision surgery. At initial and revision surgery, 47% and 88% of the pathogens were amoxicillin/clavulanic acid-resistant. Treatment outcome was favorable in 24 of 30 patients (80%) and in six cases (20%) an amputation had to be performed. None of the patients had chronic bone infection. CONCLUSIONS: Positive cultures were found often in open fractures. Amoxicillin/clavulanic acid which is often mentioned in many guidelines as prophylaxis in open fractures does not cover the most common isolated organisms. The combination of surgery and antibiotic prophylaxis leads to good outcome in Gustilo type III fracture.

Program : Brunnshusets teater : Phi-Phi

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Legume rotation effects on early growth and rhizosphere microbiology of sorghum in West African soils

Cereal yield increases in legume rotations on west African soils were the subject of much recent research aiming at the development of more productive cropping systems for the mainly subsistence-oriented agriculture in this region. However, little has been done to elucidate the possible contribution of soil microbiological factors to these rotation effects. Therefore a pot trial was conducted using legume rotation and continuous cereal soils each from one site in Burkina Faso and two sites in Togo where cropping system experiments had been conducted over 4 yrs. All soils were planted with seedlings of sorghum (Sorghum bicolor L. Moench). From 21 days after sowing onwards relative growth rates in rotation soils were higher than in the continuous cereal soils, resulting in between 69 and 500% higher shoot dry matter of rotation sorghum compared to sorghum growing in continuous cereal soils. Across sites rotation soils were characterized by higher pH, higher microbial N and a lower microbial biomass C/N ratio and, with the exception of one site, a higher fungal biomass in the rhizosphere. The bacterial and eukaryal community structure in the soil, assessed by denaturing gradient gel electrophoresis (DGGE), differed between sites. However, only at one site differed the bacterial and the eukaryal community structure in the rotation soil significantly from that in the continuous cereal soil. Although the results of this study confirmed the marked plantgrowth differences between sub-Saharan legume-rotation soils and their continuous cereal counterparts they also showed the difficulties to differentiate possible microbiological causes from their effects.

Intestinal microbiology in Crohn's disease: a study of Escherichia coli as a potential etiologic agent

La malaltia de Crohn és una malaltia inflamatòria intestinal crònica d'etiologia encara desconeguda. Actualment es pensa que hi participen factors genètics i immunològics que confereixen una susceptibilitat a l'hoste, i factors externs o ambientals, com serien els microorganismes i/o l'estil de vida. L'objectiu principal d'aquest treball ha estat descriure les poblacions bacterianes associades especialment als malalts de Crohn, amb la intenció d'identificar possibles agents etiològics. Els resultats d'aquest treball coincideixen amb investigacions prèvies que descriuen l'alteració bacteriana present en els malalts de Crohn (disbiosi) i recolzen la hipòtesi que implica el recentment descrit patovar "Adherent- Invasive Escherichia coli" (AIEC) en l'etiologia d'aquesta malaltia inflamatòria intestinal. A més, contribuïm a la descripció de les poblacions d'E. coli associades a la mucosa intestinal aportant dades sobre aspectes ecològics i patogènics. Finalment, descrivim nous aspectes fenotípics d'AIEC que podrien estar relacionats amb la seva patogènia, com seria la capacitat de formar biofilms.

Microbiology of the human intestinal tract and approaches for its dietary modulation

Gut bacteria can be categorised as being either beneficial or potentially pathogenic due to their metabolic activities and fermentation end-products. Health-promoting effects of the microflora may include immunostimulation, improved digestion and absorption, vitamin synthesis, inhibition of the growth of potential pathogens and lowering of gas distension. Detrimental effects are carcinogen production, intestinal putrefaction, toxin production, diarrhoea/constipation and intestinal infections. Certain indigenous bacteria such as bifidobacteria and lactobacilli are considered to be examples of health-promoting constituents of the microflora. They may aid digestion of lactose in lactose-intolerant individuals, reduce diarrhoea, help resist infections and assist in inflammatory conditions. Probiotics, prebiotics and synbiotics are functional foods that fortify the lactate producing microflora of the human or animal gut.

Increased whole grain consumption does not affect blood biochemistry, body composition or gut microbiology in healthy low habitual whole grain consumers

Background Whole grain (WG) foods have been suggested to reduce the risk of cardiovascular disease, but studies are inconsistent and effects on cardiovascular risk markers are not clear. Objective The objective of this study was to assess the impact of increasing WG consumption to at least 80 g/d on overall dietary intake, body composition, blood pressure (BP), blood lipids, blood glucose, gastrointestinal microbiology and gastrointestinal symptoms in healthy, middle-age adults with habitual WG intake < 24 g/d. The trial was registered as ISRCTN36521837. Methods Eligible subjects (12 men, 21 women, aged 40-65 y and BMI 20-35 kg/m2) were identified using food frequency questionnaires and subsequently completed 3-day food diaries (3DFD) to confirm habitual WG consumption. Subjects consumed diets high in WG (> 80 g/d) or low in WG (< 16 g/d, refined grain [RG] diet) in a crossover study, with 6-week intervention periods, separated by a 4-week washout. Adherence was achieved by specific dietary advice and provision of a range of cereal food products. The 3DFD, diet compliance diaries and plasma alkylresorcinols (ARs) were used to verify compliance. Results On the WG intervention, consumption increased from 28 g/d to 168 g/d (P < 0.001), accompanied by an increase in plasma ARs (P < 0.001) and total fiber intake (P < 0.001), without any effect on energy or other macronutrients. While there were no effects on studied parameters, there were trends towards increased 24 h fecal weight (P = 0.08) and reduction in body weight (P = 0.10) and BMI (P = 0.08) during the WG compared to the RG period. Conclusion A combination of dietary advice and provision of commercially available food items enabled subjects with a low-moderate habitual consumption of WG to substantially increase their WG intake, but there was little effect on blood biochemical parameters, body composition, BP, fecal measurements or gut microbiology.