Maria Gabriella Marchetti

Evaluation of the bactericidal effect of five products for surgical hand disinfection according to prEN 12054 and prEN 12791.

Surgical hand disinfection (with an alcohol-based hand rub) and surgical handwash (with an antiseptic-based liquid soap) are accepted measures to reduce the risk for surgical site infections. The new European Standards allow a comparison of their antimicrobial efficacy. The bactericidal activity of surgical hand rubs [Sterillium and Softaman, (active ingredient=alcohols)] and handwashes [Derman plus (triclosan), Hibiscrub (chlorhexidine) and Betadine (PVP-iodine)] was tested according to the prEN 12054 suspension test using Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus hirae, and to prEN 12791 for the effect on resident skin flora in comparison with 1-propanol, 60% (v/v). All five products achieved a reduction of test bacteria within 3 min of >10(5)-fold so fulfilling prEN 12054. However, only Hibiscrub, Sterillium and Softa Man met the requirements of prEN 12791, giving a mean reduction of resident micro-organisms (immediate and sustained effect) which was not significantly lower than the reference alcohol (P>0.1; Wilcoxon matched-pairs signed-rank test). Sterillium was significantly more effective than the reference alcohol (immediate and sustained affect). Products for surgical hand disinfection may have equal antimicrobial activity in suspension tests but show large differences under practical conditions. Healthcare workers should not rely on results from suspension tests when deciding on a product for surgical hand disinfection.

Monitoring Key Parameters in Bioprocesses Using Near-Infrared Technology

Near-infrared spectroscopy (NIRS) is known to be a rapid and non-destructive technique for process monitoring. Bioprocesses are usually complex, from both the chemical (ill-defined medium composition) and physical (multiphase matrix) aspects, which poses an additional challenge to the development of robust calibrations. We investigated the use of NIRS for on-line and in-line monitoring of cell, substrate and product concentrations, during aerobic and anaerobic bacterial fermentations, in different fermentation strategies. Calibration models were built up, then validated and used for the automated control of fermentation processes. The capability of NIR in-line to discriminate among differently shaped bacteria was tested.

Innovative vaccination protocol against vibriosis in Dicentrarchus labrax (L.) juveniles: Improvement of immune parameters and protection to challenge

The effect of vaccination on immune parameters of European sea bass, Dicentrarchus labrax, is not fully established, as well as surveyed throughout rearing till the commercial size. Furthermore, available information on the possible role of booster treatments is scarce. Sea bass juveniles were vaccinated against Listonella anguillarum using a commercial bivalent formulation administered by immersion (priming: 95 dph; booster: 165 dph) or by immersion (priming: 95 dph; booster: 165 dph) and subsequent i.p. injection (booster: 233 dph). Serum specific IgM and numbers of IgM(+) cells in head kidney and spleen evidenced B-cell responses mainly after the immersion booster, accompanied by increased TcR-β transcripts and leucocyte respiratory burst. Immune enhancement was confirmed by the protection towards i.p. challenges with a virulent strain. RPS accounted for >70% in fish immersion-boosted and near 100% in fish further boosted i.p. Differently from usual farm practices, this innovative vaccination protocol proved to be highly effective. Booster treatments are therefore strongly recommended.

Development of FT-NIR Models for the Simultaneous Estimation of Chlorophyll and Nitrogen Content in Fresh Apple (Malus Domestica) Leaves

Agricultural practices determine the level of food production and, to great extent, the state of the global environment. During the last decades, the indiscriminate recourse to fertilizers as well as the nitrogen losses from land application have been recognized as serious issues of modern agriculture, globally contributing to nitrate pollution. The development of a reliable Near-Infra-Red Spectroscopy (NIRS)-based method, for the simultaneous monitoring of nitrogen and chlorophyll in fresh apple (Malus domestica) leaves, was investigated on a set of 133 samples, with the aim of estimating the nutritional and physiological status of trees, in real time, cheaply and non-destructively. By means of a FT (Fourier Transform)-NIR instrument, Partial Least Squares (PLS) regression models were developed, spanning a concentration range of 0.577%–0.817% for the total Kjeldahl nitrogen (TKN) content (R2 = 0.983; SEC = 0.012; SEP = 0.028), and of 1.534–2.372 mg/g for the total chlorophyll content (R2 = 0.941; SEC = 0.132; SEP = 0.162). Chlorophyll-a and chlorophyll-b contents were also evaluated (R2 = 0.913; SEC = 0.076; SEP = 0.101 and R2 = 0.899; SEC = 0.059; SEP = 0.101, respectively). All calibration models were validated by means of 47 independent samples. The NIR approach allows a rapid evaluation of the nitrogen and chlorophyll contents, and may represent a useful tool for determining nutritional and physiological status of plants, in order to allow a correction of nutrition programs during the season.

Optimized Production of Xylitol from Xylose Using a Hyper-Acidophilic Candida tropicalis

The yeast Candida tropicalis DSM 7524 produces xylitol, a natural, low-calorie sweetener, by fermentation of xylose. In order to increase xylitol production rate during the submerged fermentation process, some parameters-substrate (xylose) concentration, pH, aeration rate, temperature and fermentation strategy-have been optimized. The maximum xylitol yield reached at 60–80 g/L initial xylose concentration, pH 5.5 at 37 °C was 83.66% (w/w) on consumed xylose in microaerophilic conditions (kLa = 2·h−1). Scaling up on 3 L fermenter, with a fed-batch strategy, the best xylitol yield was 86.84% (w/w), against a 90% of theoretical yield. The hyper-acidophilic behaviour of C. tropicalis makes this strain particularly promising for industrial application, due to the possibility to work in non-sterile conditions.

A comparative study of some soluble proteins of the genus Diplodus (Sparidae: Teleostei)

Abstract 1. 1. Soluble eye lens and muscle proteins of four species of the genus Diplodus (D. annularis, D. sargus, D. vulgaris, D. puntazzo ) were analyzed. 2. 2. Species-specific electrophoretic and isoelectric focusing patterns were found in both protein systems. 3. 3. Comparison of the soluble proteins of the eye lens and of the soluble proteins of the white skeletal muscle of the four species gave evidence that D. annularis and D. sargus are closely related and that they are only distantly related to D. vulgaris . 4. 4. Comparison also showed the relative taxonomic distance of D. puntazzo and, thus, the early detachment of this species from a presumptive common ancestral lineage.

Genetic, developmental and comparative analysis of LDH, MDH and GPI isozymes in the sheepshead bream (Diplodus puntazzo GM.)

Abstract 1. 1. The pattern of expression of lactate dehydrogenase, malate dehydrogenase and glucosephosphate isomerase isozymes were investigated in both embryonic stages and differentiated adult tissues of Diplodus puntazzo . 2. 2. The patterns of this species were compared with those of two distantly related Sparidae species ( Sparus aurata, D. sargus ). 3. 3. Species-specific patterns were found in all protein systems. 4. 4. Differences in enzyme-locus expression were used to infer the extent of species divergence. 5. 5. Some locus expression diverged markedly among species, while other were preserved. 6. 6. Comparative analysis of the enzymes examined showed the existence of a taxonomic distance between these three Sparidae species.

Quantification of Lycopene, β-Carotene, and Total Soluble Solids in Intact Red-Flesh Watermelon (Citrullus lanatus) Using On-Line Near-Infrared Spectroscopy

A great interest has recently been focused on lycopene and β-carotene, because of their antioxidant action in the organism. Red-flesh watermelon is one of the main sources of lycopene as the most abundant carotenoid. The use of near-infrared spectroscopy (NIRS) in post-harvesting has permitted us to rapidly quantify lycopene, β-carotene, and total soluble solids (TSS) on single intact fruits. Watermelons, harvested in 2013–2015, were submitted to near-infrared (NIR) radiation while being transported along a conveyor belt system, stationary and in movement, and at different positions on the belt. Eight hundred spectra from 100 samples were collected as calibration set in the 900–1700 nm interval. Calibration models were performed using partial least squares (PLS) regression on pre-treated spectra (derivatives and SNV) in the ranges 2.65–151.75 mg/kg (lycopene), 0.19–9.39 mg/kg (β-carotene), and 5.3%–13.7% (TSS). External validation was carried out with 35 new samples and on 35 spectra. The PLS models for intact watermelon could predict lycopene with R2 = 0.877 and SECV = 15.68 mg/kg, β-carotene with R2 = 0.822 and SECV = 0.81 mg/kg, and TSS with R2 = 0.836 and SECV = 0.8%. External validation has confirmed predictive ability with R2 = 0.805 and RMSEP = 16.19 mg/kg for lycopene, R2 = 0.737 and RMSEP = 0.96 mg/kg for β-carotene, and R2 = 0.707 and RMSEP = 1.4% for TSS. The results allow for the market valorization of fruits.

Separation and quantitative determination of carbohydrates in microbial submerged cultures using different planar chromatography techniques (HPTLC, AMD, OPLC).

Carbohydrates are the principal sources of nutrient and energy in large-scale submerged fermentation processes. A method for detection and quantification of sugar levels are very advantageous because they can be considered as key indicators in determining the yields and the productivity of the process. For this reason, the objective of this study is to develop and validate a simple and relatively economical analytical method for detecting complex sugar mixtures in fermentation broth based on High-Performance Thin-Layer Chromatography (HPTLC). HPTLC is a widely used, fast and accurate method of separating complex mixtures. The proposed method involved the chromatographic separations of xilo-, galacto-, fructo-oligosaccharides mixtures at different molecular weights, tri- and disaccharides (raffinose, sucrose, lactose), and the corresponding monosaccharides (xylose, fructose, galactose) on HPTLC plates, using different eluent mixtures and elution conditions. The documentation of plates was performed using TLC visualization device and the images of plates were processed using a digital processor. HPTLC methods development using instrumental techniques as OPLC (Over Pressure Liquid Chromatography) and AMD (Automated Multiple Development) has been also described, as to simultaneously monitor several samples in the same elution, with significant time and solvent savings. Four different carbohydrates complex mixtures were analyzed using HPTLC techniques, as to optimize the quality of the separation among components. The methods set up were then applied for quantitative determination of sugars. As a model of submerged fermentations, a strain of Bifidobacterium spp. was used, a saccharolytic bacterium with probiotic activities in the human gut, able to anaerobically ferment complex sugar mixtures. Results could be easily extended to other fermentation processes.

Hospital use of decontaminating mats

Decontaminating mats made of several layers of adhesive sheets (water-based acrylic 6 g/m2) supplemented with a bactericidal agent (3-1 benzoisothiazolin) at a concentration of 25% were placed in the passages providing access to the operating rooms of an orthopaedic service. Contact plates containing tryptone soy agar were used to assess bacterial concentration at specific points in front of and beyond the mats. For trolley passageways two areas were defined: central and lateral paths, corresponding to the areas walked upon by the personnel pushing the trolleys and to the paths covered by the trolley wheels, respectively. In order to exclude a simple mechanical effect, a comparison of bacterial loads at defined sites beyond the mats was carried out in the presence and in the absence of decontaminating mats. Bacterial colony counts in the presence of decontaminating mats were substantially and statistically significantly reduced compared with the absence of mats. The lower mean number of colony-forming units detected at points located beyond the mats parallels this finding; this difference is also statistically significant. We thus conclude that decontaminating mats are potentially useful in decreasing micro-organism carry-over due to personnel or the passage of trolleys into areas at high risk of infection such as operating rooms.