Dual-species relations between Candida tropicalis isolated from apple juice ultrafiltration membranes, with Escherichia coli O157:H7 and Salmonella sp.

AIMS: The objective of this study was to determine the interactions between common spoilage yeast, Candida tropicalis, isolated from ultrafiltration membranes, and Escherichia coli O157:H7 and Salmonella sp. on stainless steel surfaces. METHODS AND RESULTS: Single and dual-species attachment assays were performed on stainless steel at 25°C using apple juice as culture medium. The growth of Salmonella sp. rose when it was co-cultivated with C. tropicalis in dual biofilms at 16 and 24 h; the same effect was observed for E. coli O157:H7 at 24 h. The colonization of C. tropicalis on stainless steel surfaces was reduced when it was co-cultivated with both pathogenic bacteria, reducing C. tropicalis population by at least 1.0 log unit. Visualization by SEM demonstrated that E. coli O157:H7 and Salmonella sp. adhere closely to hyphal elements using anchorage structures to attach to the surface and other cells. CONCLUSIONS: These results suggest a route for potential increased survival of pathogens in juice processing environments. These support the notion that the species involved interact in mixed yeast-bacteria communities favouring the development of bacteria over yeast. SIGNIFICANCE AND IMPACT OF THE STUDY: This study support the plausibility that pathogen interactions with strong biofilm forming members of spoilage microbiota, such as C. tropicalis, might play an important role for the survival and dissemination of E. coli O157:H7 and Salmonella sp. in food-processing environments.

Influenza season 2012-2013 in Europe: moderate intensity, mixed (sub)types.

This paper summarizes influenza activity in the European Union/European Economic Area (EU/EEA) in 2012-2013. The influenza season 2012-2013 in Europe lasted from early December to late April. Overall the severity of the season could be described as moderate, based on the ILI/ARI consultation rates and the percentage of sentinel specimens positive for influenza compared to previous seasons. Both influenza A and B viruses circulating accounted for 47% and 53% of positive sentinel specimens, respectively, with both A(H1) and A(H3) varying for dominance. Compared to outpatients, the proportion of laboratory-confirmed influenza hospitalized cases infected by A(H1N1)pdm09 was significantly higher in middle-aged patients (33% vs. 17%, χ 2 = 66·6, P < 0·01). Despite a relatively good match between vaccine and circulating strains, vaccine effectiveness was estimated to be moderate.

Fractal dimension and mechanism of aggregation of apple juice particles.

Turbidity of freshly squeezed apple juice is produced by a polydisperse suspension of particles coming from the cellular tissue. After precipitation of coarse particles by gravity, only fine-colloidal particles remain in suspension. Aggregation of colloidal particles leads to the formation of fractal structures. The fractal dimension is a measure of the internal density of these aggregates and depends on their mechanism of aggregation. Digitized images of primary particles and aggregates of depectinized, diafiltered cloudy apple juice were obtained by scanning electron microscopy (SEM). Average radius of the primary particles was found to be a = 40 ± 11 nm. Maximum radius of the aggregates, R(L), ranged between 250 and 7750 nm. Fractal dimension of the aggregates was determined by analyzing SEM images with the variogram method, obtaining an average value of D(f) = 2.3 ± 0.1. This value is typical of aggregates formed by rapid flocculation or diffusion limited aggregation. Diafiltration process was found to reduce the average size and polydispersity of the aggregates, determined by photon correlation spectroscopy. Average gyration radius of the aggregates before juice diafiltration was found to be R(g) = 629 ± 87 nm. Average number of primary particles per aggregate was calculated to be N = 1174.

The rheology of colloidal and noncolloidal food dispersions.

Rheological data on a food together with data on its composition and structure or microstructure should lead to understanding the interrelationships between them. A number of foods are dispersions of solids in liquids, liquids in liquids, or gas in liquids. The dispersed particles may be colloidal in nature with dimensions < 10 mum, or larger noncolloidal particles (> 10 mum). For both colloidal and noncolloidal dispersions (either in dilute or concentrated regimes), several theoretical equations exist that provide insights into the role of key rheological parameters, such as particle volume fraction and size, interparticle forces, and fractal dimension on their viscosity, yield stress, and modulus. When theoretical models cannot be easily applied to foods with complex structures, structural analysis and structure-based models provide insight into the role of solids loading and interparticle bonding on rheological behavior. In this review, recent studies on colloidal and noncolloidal food dispersions in which theoretical models as well as structural analysis were employed are discussed.

Early heart rate variations during head-up tilt table testing as a predictor of outcome of the test.

Head-up tilt table testing (HUTT) is a useful tool for the diagnosis of unknown origin of syncope. A setback is its duration. This study tries to establish a specific parameter that, according to the heart rate elevation in the test's initial phase, allows a reliable prediction of its outcome. In a prospective study, every patient being under unknown syncope workup was included. A two-phase 20-minute tilt table test was performed. The initial phase was passive, and the second required pharmacological stimulation with isoproterenol. The basal and 5- and 10-minute heart rate values of the passive phase were measured and compared within the group and against negative tests. During a 1-year period, 115 HUTT were performed: 88 were positive and 27 negative. The negative HUTT patients had an increase in HR of 5.05 (+/- 13.5) beats/min at 5 minutes, and 5.79 (+/- 12.9) beats/min at 10 minutes (P = 0.2). Those with a positive HUTT had an increase of 9.05 (+/- 14.5) beats/min at 5 minutes, and of 10 (+/- 13.4) beats/min at 10 minutes (P < 0.001). There were no significant changes in HR when comparing positive to negative HUTT. There is no specific number that allows predication of outcome early in HUTT. Within the group, variations are important. Only a group tendency can be established, which strongly correlates with the results obtained during the test.

Iatrogenic renal vascular injury.

Bilateral arteriovenous fistulas secondary to percutaneous needle biopsy of each kidney developed in a patient with malignant hypertension and chronic failure. The fistulas with aneurysmal formation and hematuria were of such magnitude that bilateral nephrectomy was required for control. The patient is now normotensive and is maintained on hemodialysis. The advisability of renal needle biopsy in uncontrolled hypertension is questioned. Cases of intrarenal arteriovenous fistulas resulting from percutaneous needle biopsy of the kidney are being reported with increasing frequency. The exact incidence of fistula formation after kidney biopsy is unknown, but several series based on arteriographic studies show an incidence as high as 18 per cent. Although many of these fistulas disappear spontaneously, approximately 4 per cent persist. A review of the literature failed to reveal the incidence of aneurysmal formation. Our case was complicated by formation of bilateral renal arteriovenous fistulas secondary to repeat bilateral percutaneous needle biopsy and right open renal biopsy. Subsequent gross hematuria from the right ureteral orifice also resulted which was proved by cystoscopy and required replacement with several units of blood. The likelihood of rupture led to bilateral nephrectomy.