Effect of Origanum vulgare essential oil on biofilm formation and motility capacity of Pseudomonas fluorescens strains isolated from discoloured Mozzarella cheese.

AIMS: The study was focused on Pseudomonas fluorescens strains isolated from Mozzarella cheese, with the aim of evaluating the effects of Origanum vulgare L. essential oil (OEO) on the biofilm formation and eradication, as well as on the motility and blue pigment production at 10°C. METHODS AND RESULTS: Microdilution method was used to determine the minimum inhibitory and bactericidal concentration of the OEO, which ranged between 10 and 40 µl ml-1 . In vitro studies demonstrated that a sublethal concentration of OEO influenced not only P. fluorescens growth and motility but also the capability to form biofilm and, in a lower degree, the biofilm eradication at 10°C. Analysis by confocal microscopy revealed a dramatic reduction in biofilm formation and thickness, with scattered damage or death of cells, stained by propidium iodide. In addition, a concentration of 5 µl ml-1 of OEO affected the motility of the cells and, in particular, their ability to swim. However, the essential oil did not inhibit the blue pigment production by any of the tested strains. CONCLUSIONS: The present findings suggest that oregano essential oil inhibits the biofilm formation of P. fluorescens strains and alters their motility. Moreover, in the preformed biofilm, OEO contributes to the detachment of the cells, deteriorating the architecture of the biofilm and reducing its thickness. SIGNIFICANCE AND IMPACT OF THE STUDY: The O. vulgare L. essential oil was revealed as a promising agent against biofilm formation and for its detaching; these results suggest that oregano EO could be used in the dairy food industry to control biofilm formation, as an alternative, or in combination with conventional sanitizers.

Diversity of food-borne Bacillus volatile compounds and influence on fungal growth.

AIMS: To evaluate the antifungal activity of the volatile organic compounds (VOCs) produced by 75 different food-borne Bacillus species against Aspergillus niger, Aspergillus flavus, Aspergillus parasiticus, Aspergillus clavatus, Fusarium oxysporum f. sp. lactucae and Moniliophthora perniciosa and to determine the VOCs responsible for the inhibition. METHODS AND RESULTS: Bacillus strains inhibited fungal growth, although with different inhibition grades, with Bacillus subtilis, Bacillus amyloliquefaciens and Bacillus cereus strains as the best antifungal VOCs producers. While M. perniciosa DM4B and F. oxysporum f.sp. lactucae MA28 were the most sensitive fungi, A. parasiticus MG51 showed the greatest resistance to Bacillus VOCs exposure. Thirty-seven compounds were detected by SPME-GC-MS analysis, although similar patterns in volatile compounds were evidenced within the species, interspecific VOCs differences determined different effects on fungal growth. Multiple partial least regression (MPLRS) and antifungal activity of the individual VOCs revealed that only propanone, 1-butanol, 3-methyl-1-butanol, acetic acid, 2-methylpropanoic acid, carbon disulphide, 3-methylbutanoic acid and ethyl acetate were responsible for mycelia inhibition of M. perniciosa DM4B and F. oxysporum f.sp. lactucae MA28. CONCLUSIONS: The antagonistic activity of the Bacillus VOCs was demonstrated, although it cannot easily be explained through the action of a single molecule, thus a holistic approach could be more appropriate to estimate the fungal growth inhibition. SIGNIFICANCE AND IMPACT OF THE STUDY: VOCs produced by Bacillus from cooked food can be considered as promising antifungal compounds useful in the control of fungal plant pathogens. This study investigates for the first time the correlation between mycelia inhibition of M. perniciosa and F. oxysporum f. sp. lactucae and the VOCs emitted by the Bacillus species.

Measuring consumer effort in circular economy initiatives in the food domain: An exploratory analysis.

The transition towards a Circular Economy (CE) system requires a change in consumers' behavioural pattern that implies a certain level of effort which, in turn, could affect initiatives' success. Although consumers' role in CE is increasingly drawing the attention of scholars, limited knowledge is available on the evaluation of consumer's effort in CE initiatives. The current research provides an identification and measurement of the core parameters affecting consumer effort, offering a comprehensive Effort Index applied to 20 CE companies operating in food domain. Companies were classified in 5 categories (Quantity of food, Appearance of food, Edibility of food, Living with food and Local and sustainable food); the analysis of the companies revealed 14 parameters building the Effort Index. Results showed that initiatives ascribable to the category "Local and sustainable food" require higher levels of consumer effort; in contrast, case studies belonging to "Edibility of food" group are less effort-requiring.

Electronic paramagnetic resonance investigation of the activity of Origanum vulgare L. essential oil on the Listeria monocytogenes membrane.

AIMS: To evaluate the effect of oregano essential oil on Listeria monocytogenes cytoplasmic membrane. METHODS AND RESULTS: Nitroxide free-radical Electron Paramagnetic Resonance was applied on L. monocytogenes after 30 min exposure to oregano essential oil concentrations ranging from 0 to 1.25%. The impact of essential oil on the number of viable cells was evaluated by plate count. Growth dynamics of survivors in BHI and TSB were evaluated by turbidometry. After exposure to essential oil concentrations up to 0.50%, the membrane fluidity was changed and its order increased. When L. monocytogenes was exposed to higher concentrations, membrane order parameters slightly returned to the values of untreated cells. However, when the cells were exposed to EO in the presence of sodium azide, which impairs energy metabolism, the membrane fluidity was progressively enhanced, even at the lowest EO concentration (0.25%). Microbiological analyses confirmed a progressive reduction of viable count, at increasing essential oil concentrations. Both in BHI and TSB, the Lag phase length increased in treated cells with respect to controls, suggesting a cell damage recovery. CONCLUSIONS: The combined approach including microbiological and EPR analyses provided relevant information on membrane modification and cell response to essential oils. SIGNIFICANCE AND IMPACT OF THE STUDY: EPR approach was demonstrated to be an effective and helpful tool to comprehend the modifications exerted by essential oil on the bacterial membrane.

Growth and metabolites production by Penicillium brevicompactum in yoghurt.

Penicillium brevicompactum, commonly encountered in the indoor air, is known to produce a mycotoxin, mycophenolic acid (MPA). This mould has been isolated from a wide range of foods; considering that we had previously isolated this species from contaminated yoghurt, in this study we have evaluated its growth in yoghurt sweetened with sucrose, fructose and fructose added with fruit pieces. Fungal growth was evaluated monitoring CO(2) production in the headspace during yoghurt storage at 4+/-1, 8+/-1 and 10+/-1 degrees C throughout 21 days. P. brevicompactum grew well in the samples sweetened with fructose at 8 and 10 degrees C. The addition of sucrose influenced the growth negatively, particularly at 4 degrees C. Volatile Organic Compounds (VOC) and MPA production was determined at 8 degrees C in inoculated and uninoculated yoghurt, as well as in liquid malt extract. Differences in VOC profiles and in MPA production were correlated with the age of the fungus and with the growth medium. This study points out for the first time the early qualitative changes in volatile production patterns of a common indoor mould, grown in yoghurt, as well as the production of MPA during storage at refrigeration temperatures.

Antimicrobial activity of Austroeupatorium inulaefolium (H.B.K.) against intracellular and extracellular organisms.

The antimicrobial activity of Austroeupatorium inulaefolium (H.B.K.) essential oil was studied in different pathogens species and its cytotoxicity activity was determinated on different cellular lines. Despite the good antibacterial activity of A. inulaefolium, it has been cytotoxic at low concentrations. Consequently it might be interesting to determine the antimicrobial activity and cytotoxicity of the major compounds of this essential oil.

Intracranial hypertension in head injury: management and results.

OBJECTIVE: (1) To describe the pattern of intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in a group of severe head-injured patients, (2) to quantify complications of ICP monitoring, and (3) to describe a management protocol and its results. DESIGN: Prospective observational study. SETTING: General intensive care unit in a teaching hospital. PATIENTS: 138 comatose patients, selected according to the following criteria: age > 16 years, coma [Glasgow Coma Scale (GCS) < or = 8] with at least one pupil reactive after resuscitation, digital recording of intracranial and arterial pressure, and jugular saturation measurements. MEASUREMENTS AND RESULTS: Median GCS was 5, and 62 patients had significant extracranial injuries; 71 had intracranial hematomas, which were urgently evacuated. Mean ICP was 20.5 mmHg (SD 8.34), mean CPP was 71.86 mmHg (SD 11.22); cerebral extraction of oxygen averaged 29 %. Medical therapy was used to control ICP in 130 cases; 93 patients required hyperventilation. Vasopressors were infused in 16 cases; in 14 cases a barbiturate infusion was started. In 6 patients all pharmacological treatments failed and surgical decompression was done. The only complication of ICP monitoring was meningitis in 3 patients. Outcome at 6 months was a good recovery and moderate disability for 82 patients (59.4%), severe disability and vegetative status for 37 (26.8%), and 19 patients died (13.7%). The severity of intracranial hypertension was related to poorer results at 6 months. CONCLUSIONS: Intracranial hypertension is very frequent in severe head injury but can be reasonably well controlled by combined surgical and medical therapy.

Cerebral venous oxygen saturation studied with bilateral samples in the internal jugular veins.

The current literature reports many measurements (arteriovenous oxygen content difference and cerebral metabolic rate of oxygen, etc.) with samples from the internal jugular veins (IJs), obtained from either side of the neck, based on the assumption that a reliable sample of mixed venous blood can be drawn. We compared oxygen saturation in both IJs in 32 patients with head injuries to establish the similarities or discrepancies in the two veins. Both IJs were cannulated with 20-G catheters; in five patients, a fiberoptic catheter was used to obtain a continuous recording of the hemoglobin saturation. Blood samples were taken simultaneously from the two IJs and immediately processed; the total number of samples processed was 342, with an average of 5.34 paired samples from each patient. The mean and the standard deviation of the differences between the saturation of the two IJs were, respectively, 5.32 and 5.15. Fifteen patients showed differences greater than 15% in hemoglobin saturation; three more patients showed differences greater than 10% at some point during the investigation. Ultimately, only eight patients had differences of less than 5%. No relationship was found among the computed tomographic scan data and the pattern of hemoglobin saturation detected. Therefore, we were not able to identify the side more appropriate for monitoring in patients with bilateral, predominantly monolateral, cortical, or deeply located lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Complications and safety associated with ICP monitoring: a study of 542 patients.

In our institution ICP was monitored in patients with GCS < or = 8 and abnormal CT scan: 362 severely head injured and 180 subarachnoid hemorrhage. Mean duration of monitoring was 103.6 hours (SD 74.96). Among 542 patients, 440 showed at least one episode of ICP above the threshold of 20 mm Hg. Among 362 head injured patients only 71 (19.3%) had an ICP lower than 20 mm Hg. In the remaining 289 (81.7%) at least one episode > or = 20 mm Hg was measured. In 13 cases (2.2%) a ventricular infection has been diagnosed. In 1 case an intraparenchimal hemorrhage related to the presence of the catheter was detected. Elevated risk of HICP and low incidence of complications have been shown in this series.

Growth modelling of the predominant microbial groups in hamburgers in relation to the modulation of atmosphere composition, storage temperature, and diameter of meat particle.

The gas composition, storage temperature, and diameter of meat particles in modified-atmosphere-packaged hamburgers were modulated according to a Central Composite Design with the aim of assessing the effects of these variables and their interaction on the predominant spoilage microbial groups, gas atmosphere and colour modifications. The parameters of the growth curves, analyzed according to the Gompertz equation, as well as the rate of gas composition and colour modification, were analyzed in order to obtain polynomial equations. The model obtained emphasized the role attributable to a structural variable such as the diameter of particles and to its interaction with atmosphere composition and temperature. Brochothrix thermosphacta was the organism endowed with the highest growth potential in the three-dimensional space defined by the range of the variables taken into consideration. The iso-response surfaces obtained and a comparison of the responses of the various groups permit the identification of the conditions able to reduce the growth of potentially hazardous micro-organisms.

Characterization of the Enterobacteriaceae isolated from an artisanal Italian ewe's cheese (Pecorino Abruzzese).

AIMS: To evaluate some physiological characteristics of the Enterobacteriaceae isolated from Pecorino cheese. METHODS AND RESULTS: The production of organic acids, secondary volatile compounds, biogenic amines (BA) and the lipolytic and proteolytic activities of Citrobacter braakii, Enterobacter sakazakii, Escherichia coli, Kluyvera spp., Salmonella enterica ssp. arizonae and Serratia odorifera strains were determined in skim milk after 48 h of fermentation at 30 degrees C. The proteolytic activity observed only in Ser. odorifera and Kluyvera spp. was confirmed by the peptide profiles of the pH 4.6-insoluble fraction using RP-HPLC; however, the lipase activity was evidenced in all the isolates of E. coli, Kluyvera spp. and Salm. enterica ssp. arizonae. During fermentation, all the strains utilized citric acid and produced significant quantities of putrescine followed by histamine, spermine and spermidine as well as acetic and lactic acid. Moreover, the major volatile compounds produced were ethanol, 2,3-butanedione, 3-hydroxy-2-butanone, 2-heptanone and acetone. CONCLUSIONS: The Enterobacteriaceae of dairy origin possess many metabolic activities that could affect the sensory quality of the cheese in which they grow during ripening. SIGNIFICANCE AND IMPACT OF THE STUDY: The important physiological characteristics possessed by Enterobacteriaceae confirm the complexity of the microbiota of Pecorino Abruzzese cheese, which influences the typical sensory properties of this product.

[Molecular diagnosis of non-Hodgkin B lymphomas by capillary electrophoresis and Genescan analysis: a molecular pathology laboratory experience]. / La diagnosi molecolare dei linfomi non-Hodgkin B in Genescan mediante elettroforesi capillare: l'esperienza di un laboratorio ospedaliero di patologia molecolare.

PCR protocols for immunoglobulin heavy chain (IgH) gene rearrangements amplification make easy the NHL-B identification. In this study we analyzed PCR products by Capillary Electrophoresis (CE) and GeneScan (GS) software, wich offers clear advantages over the conventional methods such as agarose gels (AGGE), characterized by hight rate of false negative and false positive results. We suggested some criteria--not included in previous NHL-B issues--useful to a correct analysis of results in GS. Since 2003, we collected 2,977 samples (2,770 peripheral blood and bone marrow, and 207 tissues) for GS analysis from NHL-B patients. At beginning PCR products were detected by both AGGE and CE. FR2 and FR3 VH regions were amplified by PCR seminested; together with Bcl-6 "housekeeping" gene from the same sample, as marker of DNA quality and PCR efficiency. Bcl-2/IgH and Bcl1/IgH traslocations were also analyzed for follicular and mantle cells lymphomas respectively. Resolution and sensitivity tests, developed with serial diluitions of clonal products in water and in DNA from healthy individuals, showed for GS 1% of resolution limit (3% AGGE) and 0.5% of sensitivity (5% AGGE). Our criteria for correct interpretations of results are: a) use of "house-keeping" gene Bcl-6; b) costant reference scales for hight and molecular weight; c) clonal peak at least twice higher than adiacent peaks; d) position of clonal peak (central or eccentric) as regards to policlonal peaks distributions. e) peaks features for oligoclonal or biallelic rearrangements evaluation. GS is an ideal method for detecting IgH rearrangements and some characteristic traslocations. The precise determination of the size of the PCR product can be used for the minimal residual disease evaluation. Moreover, it allows semi-quantitative resolution of fragments only one base different in size and may be more objective than gel-based methods.

Modifications of electrical potential in corrosive induced lesions of rat oesophagus.

The Authors reproduced, experimentally, lesions of oesophageal mucosa on "Wistar" rats, using 1% and 2% solutions of HCl and NaOH. They studied DP modifications and observed that acid solutions produced a complete and persistent DP modification, while alkaline solutions produce DP inversions that diminish few days after the treatment.

[Increasing the pressure of cerebral perfusion to control intracranial pressure]. / Aumentare la pressione di perfusione cerebrale per controllare la pressione intracranica.

ICP control can be achieved removing the surgical masses and manipulating the intracranial compartments; in the intensive care setting that can be attempted using CSF withdrawal or changing the cerebrovascular resistances, the intracranial blood content and the cerebral water content. The reduction of the ICP and the maintenance of a good cerebral perfusion pressure are the main aims of the therapy; when any standard treatment fails to control ICP a further attempt to preserve cerebral perfusion should be done by increasing the mean arterial pressure. In 10 patients with severe brain damage (GCS on admission ranging from 3 to 7, mean 5) from subarachnoid hemorrhage (3 cases) or trauma an infusion of dopamine (25-150 mg/h) and noradrenaline (0.4-2.4 mg/h) was started in case of intractable ICP. The ICP was defined intractable when the pressure was more than 40 mmHg for more than 5 m' after maximum therapy, as evaluated using the Therapy Intensity Level score. The infusion obtained a raise of the MAP of approximately 25% and a variable response on ICP. In 9 cases ICP dropped, in one case, instead, the ICP increased together with the arterial pressure. The reduction of ICP was 20-30%, with a good improvement of the CPP. The patients with a good response survived, the only patient without control of the ICP died. The physiopathologic mechanisms of this treatment are discussed; the most suitable explanation is indicated in an autoregulatory process. The infusion of cathecolamines can be harmful, and the patients eligible for this treatment must be carefully chosen. Notwithstanding this approach deserves further studies for the cases of intractable ICP.

[Clinical use of cerebral elastance and intracranial dynamics measurements]. / Impiego clinico delle misure di elastanza cerebrale e di dinamica intracranica.

The treatment of Intracranial Pressure (ICP) requires not only the determination of the pressure but also some kind of estimate of the relationship between intracranial volume and actual pressure. The measurement of the Pressure Volume Index (PVI) offers a quantitative assessment of such a relationship, provided that the measurement is safe and accurate. In 98 comatose patients admitted to the Intensive Care Unit for the treatment of head injury or subarachnoid hemorrhage the ICP was continuously recorded using ventricular or subdural catheters. In 68 patients the PVI was measured using the bolus technique every 12 hours; the intracranial dynamics was assessed according to Marmarou's equations. The preliminary part of the work reviewed the methodology: the interobserver variability was studied and the differences between the PVI data obtained through addition or withdrawal of fluid were determined. The data obtained by different observers did not differ substantially, due to the clear establishment of rules for the measurement. The PVI data obtained withdrawing fluid were lower than the data produced adding volume but the mean PVI calculated after 6 bolus changes of the intraventricular volume reached a good correlation coefficient (> 0.8) with all the measurements. After that the clinical use of the PVI was tested. The patients with a PVI lower than 15 ml showed an increased risk of developing intracranial hypertension in the first 72 hours after trauma of SAH. The group of patients with an intracranial compliance lower than 0.5 had a mortality rate of 27.3%, compared with the rate of 14.3% showed by the patients with a greater Compliance.(ABSTRACT TRUNCATED AT 250 WORDS)

[Cerebral perfusion pressure in endocranial hypertension in comatose head-injured patients]. / Pressione di perfusione cerebrale ed ipertensione endocranica nei traumi cranici in coma.

The aim of the intensive care of the injured is the coupling of the availability and the requirement of the cerebral metabolic substates. The measurement of the cerebral blood flow is not currently available at the bedside and less direct monitoring is required. The cerebral perfusion can be estimated looking at the cerebral perfusion pressure (CPP), that can be easily measured using intracranial pressure (ICP) and the systemic arterial pressure (MAP) monitoring. Hundred-twenty-one consecutive head injured admitted to an Intensive Care Unit were studied assessing the severity of the neurological injury, the CT-Scan diagnosis of the intracranial lesion, the Trauma Score and the behavior of the ICP and MAP. The outcome was classified according to a modified version of the Glasgow Outcome Scale. More than 77% of the patients suffered raised intracranial pressure above 20 mmHg and 16 of them had a CPP less than 60 mmHg for more than 5 minutes. The outcome was directly related to the degree of intracranial hypertension and to the severity of insufficient CPP. The treatment of the severe head injured must be aimed at maintaining a good CPP, because of the close relationships between this value and the prognostic result. The monitoring of the ICP is a reliable and relatively safe procedure in this series, where the rate of infections complicating the intracranial recording is less than 3%.

Characterization of sourdough lactic acid bacteria based on genotypic and cell-wall protein analyses.

AIMS: To evaluate the effectiveness of two independent methods in differentiating a large population of lactic acid bacteria (LAB) isolated from wheat flours and sourdoughs and to correlate eventual differences/similarities among strains with their geographical origin and/or process parameters. METHODS AND RESULTS: One hundred fifty strains belonging to Lactobacillus spp. and Weissella spp., plus eight type strains, one for each species, and two unidentified isolates, were characterized by randomly amplified polymorphic DNA (RAPD) and SDS-PAGE of cell-wall proteins. The RAPD analysis separated the eight type strains but did not always assign all the strains of a species to the same group, while SDS-PAGE cell-wall protein profiles were species-specific. Frequently, strains isolated from sourdoughs of the same geographical origin or produced by similar raw material/process parameters showed similar RAPD and/or cell-wall profiles. CONCLUSIONS: The combined use of the RAPD and cell-wall protein analysis represents a useful tool to classify large adventitious microbial populations and to discriminate the diversity of the strains. SIGNIFICANCE AND IMPACT OF THE STUDY: This study represents a typing of a large collection of flour/sourdough LAB and provides evidence of the advantage of using two independent methods in the classification and traceability of microorganisms.

[Arterio-jugular difference of oxygen and intracranial pressure in comatose, head injured patients. I. Technical aspects and complications]. / Differenza artero-giugulare di ossigeno e pressione intracranica nei traumi cranici in coma. Parte I: Aspetti tecnici e complicanze.

The monitoring of the comatose head injured patients is based on the recording of several data; the intracranial pressure measurements (ICP), associated with the arterial pressure recording, gives a good estimate of the cerebral perfusion pressure (CPP) but further information about the cerebral perfusion are needed. Based on the assumption that the cerebral metabolic rate is kept constant strong relationships exist between the cerebral blood flow (CBF) and the arterovenous difference of oxygen (AVDO2). In order to obtain samples of cerebral venous blood a catheter must be inserted in the internal jugular vein (IJ) with the tip of the cannula reaching the superior jugular bulb. In 224 patients we measured the ICP trough ventricular or subdural catheters; invasive measurement of the arterial pressure was also carried on in all the patients. In 45 patients we measured the AVDO2 and we tested the safety and the reliability of the jugular vein cannulation. During the insertion of the jugular catheters a slight increase of ICP, without any clinical significance, was recorded; in two cases (on a total of 45) accidental carotid puncture occurred. In 9 cases we tested the concordance of the oxygen content between the two IJs; looking at the mean values no statistical difference is detected between the two sides but in some cases relevant differences are recorded. In two cases we inserted the catheters more cranially, reaching a sinus of the cranial basis; the blood collected from these points carries less oxygen that the blood collected in the neck. The rate of infection in this series of ICP monitoring is very low (1.78%) and we had no bleeding at the moment of the insertion of the catheters. Since no significant complications related to the IJ cannulation were recorded we conclude that these techniques are safe and can be easily performed in the clinical setting. Further studies are required in order to investigate the clinical meaning of the differences in the IJs content of oxygen.