Isolation and identification of Legionella spp. from non-hospital facilities: a preliminary one-year surveillance study in the urban area of Pesaro-Urbino (Central Italy)

BACKGROUND

Legionella is considered one of the most important causes of potentially preventable morbid-ity and mortality. These microorganisms are ubiquitous, but incomplete information is available on the geographic distribution of Legionella species in our region.

STUDY DESIGN

For the mentioned reasons, in this work the distribution of Legionella spp. in non-hospital facilities of the urban area of Pesaro-Urbino (Central Italy), including public fountains, residential build-ings, public and private offices and retirement homes, was investigated.

METHODS

A total of 298 water samples were collected from the different facilities and subjected to standard Legionella isolation and identification protocols.

RESULTS

As reported, 17.8% of the collected water samples resulted positive for Legionella spp. (28.6% from retirement homes, 21.3% from residential buildings, 15.3% from private and public offices). The highest per-centage of positive samples (14.4%) was found in hot water from retirements homes (58.8%) and residential buildings (31.8%); the most frequent isolated serogroups were L. pneumophila 2-14 (71.7%).

CONCLUSIONS

This work is the first describing the distribution of Legionella spp. in non-hospital facilities in the province of Pesaro-Urbino, and highlights a condition of potential risk for susceptible categories. From our data, we can point that a regular and constant control to prevent microbiological risk from legionellosis, particularly in facilities housing the elderly, is recommended.

Isolation of a high-affinity Bet v 1-specific IgG-derived ScFv from a subject vaccinated with hypoallergenic Bet v 1 fragments

Background

Recombinant hypoallergenic allergen derivatives have been used in clinical immunotherapy studies, and clinical efficacy seems to be related to the induction of blocking IgG antibodies recognizing the wild‐type allergens. However, so far no treatment‐induced IgG antibodies have been characterized.

Objective

To clone, express, and characterize IgG antibodies induced by vaccination with two hypoallergenic recombinant fragments of the major birch pollen allergen, Bet v 1 in a nonallergic subject.

Methods

A phage‐displayed combinatorial single‐chain fragment (ScFv) library was constructed from blood of the immunized subject and screened for Bet v 1‐reactive antibody fragments. ScFvs were tested for specificity and cross‐reactivity to native Bet v 1 and related pollen and food allergens, and epitope mapping was performed. Germline ancestor genes of the antibody were analyzed with the ImMunoGeneTics (IMGT) database. The affinity to Bet v 1 and cross‐reactive allergens was determined by surface plasmon resonance measurements. The ability to inhibit patients’ IgE binding to ELISA plate‐bound allergens and allergen‐induced basophil activation was assessed.

Results

A combinatorial ScFv library was obtained from the vaccinated donor after three injections with the Bet v 1 fragments. Despite being almost in germline configuration, ScFv (clone H3‐1) reacted with high affinity to native Bet v 1 and homologous allergens, inhibited allergic patients’ polyclonal IgE binding to Bet v 1, and partially suppressed allergen‐induced basophil activation.

Conclusion

Immunization with unfolded hypoallergenic allergen derivatives induces high‐affinity antibodies even in nonallergic subjects which recognize the folded wild‐type allergens and inhibit polyclonal IgE binding of allergic patients.

Intranasal administration of allergen increases specific IgE whereas intranasal omalizumab does not increase serum IgE levels-A pilot study

Background

Administration of the therapeutic anti‐IgE antibody omalizumab to patients induces strong increases in IgE antibody levels.

Objective

To investigate the effect of intranasal administration of major birch pollen allergen Bet v 1, omalizumab or placebo on the levels of total and allergen‐specific IgE in patients with birch pollen allergy.

Methods

Based on the fact that intranasal allergen application induces rises of systemic allergen‐specific IgE, we performed a double‐blind placebo‐controlled pilot trial in which birch pollen allergic subjects were challenged intranasally with omalizumab, placebo or birch pollen allergen Bet v 1. Total and allergen‐specific IgE, IgG and basophil sensitivity were measured before and 8 weeks after challenge. For control purposes, total, allergen‐specific IgE levels and omalizumab‐IgE complexes as well as specific IgG levels were studied in subjects treated subcutaneously with either omalizumab or placebo. Effects of omalizumab on IgE production by IL‐4/anti‐CD40‐treated PBMCs from allergic patients were studied in vitro.

Results

Intranasal challenge with Bet v 1 induced increases in Bet v 1‐specific IgE levels by a median of 59.2%, and this change differed significantly from the other treatment groups (P = .016). No relevant change in allergen‐specific and total IgE levels was observed in subjects challenged with omalizumab. Addition of omalizumab did not enhance IL‐4/anti‐CD40‐induced IgE production in vitro. Significant rises in total IgE (mean IgE before: 131.83 kU/L to mean IgE after: 505.23 kU/L) and the presence of IgE‐omalizumab complexes were observed after subcutaneous administration of omalizumab.

Conclusion

Intranasal administration of allergen induced rises of allergen‐specific IgE levels, whereas intranasal administration of omalizumab did not enhance systemic total or allergen‐specific IgE levels.

Lactose oleate as new biocompatible surfactant for pharmaceutical applications

Sugar fatty acid esters are an interesting class of non-ionic, biocompatible and biodegradable sugar-based surfactants, recently emerged as a valid alternative to the traditional commonly employed (e.g. polysorbates and polyethylene glycol derivatives). By varying the polar head (carbohydrate moiety) and the hydrophobic tail (fatty acid), surfactants with different physico-chemical characteristics can be easily prepared. While many research papers have focused on sucrose derivatives, relatively few studies have been carried out on lactose-based surfactants. In this work, we present the synthesis and the physico-chemical characterization of lactose oleate. The new derivative was obtained by enzymatic mono-esterification of lactose with oleic acid. Thermal, surface, and aggregation properties of the surfactant were studied in detail and the cytotoxicity profile was investigated by MTS and LDH assays on intestinal Caco-2 monolayers. Transepithelial electrical resistance (TEER) measurements on Caco-2 cells showed a transient and reversible effect on the tight junctions opening, which correlates with the increased permeability of 4 kDa fluorescein-labelled dextran (as model for macromolecular drugs) in a concentration dependent manner. Moreover, lactose oleate displayed a satisfactory antimicrobial activity over a range of Gram-positive and Gram-negative bacteria. Overall, the obtained results are promising for a further development of lactose oleate as an intestinal absorption enhancer and/or an alternative biodegradable preservative for pharmaceutical and food applications.

Responses of Mytilus galloprovincialis hemocytes to environmental strains of Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio vulnificus

Marine bivalves are exposed to different types of bacteria in the surrounding waters, in particular of the Vibrio genus. In the hemocytes of the mussel Mytilus spp. immune responses to different vibrios have been largely characterized. However, little information is available on the hemocyte responses to human pathogenic vibrios commonly detected in coastal waters and bivalve tissues that are involved in seafood-borne diseases. In this work, functional parameters of the hemocytes from the Mediterranean mussel M. galloprovincialis were evaluated in response to in vitro challenge with different vibrios isolated from environmental samples of the Adriatic sea (Italy): V. parahaemolyticus Conero, V. alginolyticus 1513 and V. vulnificus 509. V. parahaemolyticus ATCC 43996 was used for comparison. At the 50:1 bacteria hemocyte ratio, only V. parahaemolyticus strains induced significant lysosomal membrane destabilisation. Stimulation of extracellular lysozyme release, total ROS, O₂^- and NO production were observed, although to different extents and with distinct time courses for different vibrios, V. vulnificus 509 in particular. Further comparisons between V. parahaemolyticus Conero and V. vulnificus 509 showed that only the latter induced dysregulation of the phosphorylation state of p38 MAP Kinase and apoptotic processes. The results indicate that mussel hemocytes can mount an efficient immune response towards V. parahaemolyticus and V. alginolyticus strains, whereas V. vulnificus 509 may affect the hemocyte function. This is the first report on immune responses of mussels to local environmental isolates of human pathogenic vibrios. These data reinforce the hypothesis that Mytilus hemocytes show specific responses to different vibrio species and strains.

Infant milk formulas differ regarding their allergenic activity and induction of T-cell and cytokine responses

Background

Several hydrolyzed cow's milk (CM) formulas are available for avoidance of allergic reactions in CM‐allergic children and for prevention of allergy development in high‐risk infants. Our aim was to compare CM formulas regarding the presence of immunoreactive CM components, IgE reactivity, allergenic activity, ability to induce T‐cell proliferation, and cytokine secretion.

Methods

A blinded analysis of eight CM formulas, one nonhydrolyzed, two partially hydrolyzed (PH), four extensively hydrolyzed (EH), and one amino acid formula, using biochemical techniques and specific antibody probes was conducted. IgE reactivity and allergenic activity of the formulas were tested with sera from CM‐allergic patients (n = 26) in RAST‐based assays and with rat basophils transfected with the human FcεRI, respectively. The induction of T‐cell proliferation and the secretion of cytokines in Peripheral blood mononuclear cell (PBMC) culture from CM allergic patients and nonallergic individuals were assessed.

Results

Immune‐reactive α‐lactalbumin and β‐lactoglobulin were found in the two PH formulas and casein components in one of the EH formulas. One PH formula and the EH formula containing casein components showed remaining IgE reactivity, whereas the other hydrolyzed formulas lacked IgE reactivity. Only two EH formulas and the amino acid formula did not induce T‐cell proliferation and proinflammatory cytokine release. The remaining formulas varied regarding the induction of Th2, Th1, and proinflammatory cytokines.

Conclusion

Our results show that certain CM formulas without allergenic and low proinflammatory properties can be identified and they may also explain different outcomes obtained in clinical studies using CM formulas.

Heat-labile Escherichia coli toxin enhances the induction of allergen-specific IgG antibodies in epicutaneous patch vaccination

Epicutaneous allergen-specific immunotherapy (EPIT) is proposed as an alternative route for allergen-specific immunotherapy (AIT). The induction of allergen-specific blocking IgG antibodies represents an important mechanism underlying AIT, but has not been investigated for EPIT. Here, we compared the induction of allergen-specific blocking IgG in outbred guinea pigs which had been immunized with recombinant birch pollen allergen Bet v 1 using patch delivery system (PDS) with or without heat-labile toxin (LT) from Escherichia coli or subcutaneously with aluminum hydroxide (Alum)-adsorbed rBet v 1. Only subcutaneous immunization with Alum-adsorbed rBet v 1 and epicutaneous administration of rBet v 1 with PDS in combination with LT from E. coli induced allergen-specific IgG antibodies blocking allergic patients' IgE, but not immunization with rBet v 1 via PDS alone. Our results suggest that patch vaccination with rBet v 1 in combination with LT may be a promising strategy for allergen-specific immunotherapy against birch pollen allergy.

Enhanced detection of terrestrial gamma-ray flashes by AGILE

At the end of March 2015 the onboard software configuration of the Astrorivelatore Gamma a Immagini Leggero (AGILE) satellite was modified in order to disable the veto signal of the anticoincidence shield for the minicalorimeter instrument. The motivation for such a change was the understanding that the dead time induced by the anticoincidence prevented the detection of a large fraction of Terrestrial Gamma-Ray Flashes (TGFs). The configuration change was highly successful resulting in an increase of one order of magnitude in TGF detection rate. As expected, the largest fraction of the new events has short duration (<100 μs), and part of them has simultaneous association with lightning sferics detected by the World Wide Lightning Location Network. The new configuration provides the largest TGF detection rate surface density (TGFs/km²/yr) to date, opening prospects for improved correlation studies with lightning and atmospheric parameters on short spatial and temporal scales along the equatorial region.

Poor association of allergen-specific antibody, T- and B-cell responses revealed with recombinant allergens and a CFSE dilution-based assay

BACKGROUND

The adaptive immunity underlying allergy comprises two components, the allergen-specific antibody (i.e. IgE, IgG) and the T-cell response. These two components are responsible for different disease manifestations and can be targeted by different therapeutic approaches. Here, we investigated the association of allergen-specific antibody and T- as well as B-cell responses in pollen-allergic patients using recombinant (r) major birch pollen allergen rBet v 1 and major timothy grass pollen allergen rPhl p 5 as defined antigens.

METHODS

Allergen-specific IgE and IgG antibody responses were determined by ELISA, and allergen-specific T- and B-cell responses were measured in peripheral blood mononuclear cells using a carboxyfluorescein-diacetate-succinimidylester (CFSE) dilution assay.

RESULTS

CFSE staining in combination with T-cell- and B-cell-specific gating allowed discriminating between allergen-specific T-cell and B-cell responses. Interestingly, we identified patients where mainly T cells and others where mainly B cells proliferated in response to allergen stimulation. No association between the level of allergen-specific Ig responses and B- or T-cell proliferation was observed.

CONCLUSION

Purified recombinant allergens in conjunction with CFSE staining allow the dissection of allergen-specific B- and T-cell responses. The dissociation of allergen-specific antibody, and B- and T-cell responses may explain the occurrence of selective IgE- and T-cell-mediated manifestations of allergic inflammation and may be important for the development of diagnostic and therapeutic strategies selectively targeting B cells and T cells.

[Screening of obesity, overweight and thinness in a children population in Rome, Italy]

AIM

Objective of the study was to estimate the prevalence of obesity, overweight and thinness in a children population in Rome, Italy.

METHODS

The study sample was created, after informed consent, in a school in Rome, available to the study project. A total of 595 children (289 males, 306 females), aged between 6 to 19 years, underwent following measurements: height and weight, evaluation of body mass index.

RESULTS

A normal BMI was recorded in 73.6% of cases. Morbid obesity, obesity, overweight, and thinness grade 1 and 2 prevalence was 1.2%, 4%, 15.3%, 9.2% and 3.8%, respectively, without statistical differences in both genders, except the prevalence of overweight that resulted statistically significant (11.4% females vs. 19.3% males, P<0.05). Differences in the age groups have been found. About 17.2% and 18.7% of children between 7 to 11 years were overweight and obese and about 33.3% and 26.6% between 6 to 8 years thin grade 1 and 2, respectively.

CONCLUSION

The study suggests a prevalence of overweight and obesity in our sample lower than that reported in a recent epidemiological survey carried out on Italy. Attention must be taken to underweight, particularly with regard to the most severe form, as a public health problem for all possible risks correlated. In addition, our study shows the involvement of specific age groups. This finding, if confirmed in a larger population, should be associated with a major attention on specific age groups at risk, in order to plan an appropriate treatment program.

Allergen-specific immunotherapy: from therapeutic vaccines to prophylactic approaches

Immunoglobulin E-mediated allergies affect more than 25% of the population. Allergen exposure induces a variety of symptoms in allergic patients, which include rhinitis, conjunctivitis, asthma, dermatitis, food allergy and life-threatening systemic anaphylaxis. At present, allergen-specific immunotherapy (SIT), which is based on the administration of the disease-causing allergens, is the only disease-modifying treatment for allergy. Current therapeutic allergy vaccines are still prepared from relatively poorly defined allergen extracts. However, with the availability of the structures of the most common allergen molecules, it has become possible to produce well-defined recombinant and synthetic allergy vaccines that allow specific targeting of the mechanisms of allergic disease. Here we provide a summary of the development and mechanisms of SIT, and then review new forms of therapeutic vaccines that are based on recombinant and synthetic molecules. Finally, we discuss possible allergen-specific strategies for prevention of allergic disease.

Cigarette smoke facilitates allergen penetration across respiratory epithelium

BACKGROUND

The association between cigarette smoke exposure and allergic airway disease is a matter for debate. We sought to investigate in an in vitro system whether active smoking reduces the integrity and barrier function of the respiratory epithelium and thus facilitates allergen penetration.

METHODS

We cultured the human bronchial epithelial cell line 16HBE14o- in a transwell culture system as a surrogate for the intact respiratory epithelium. The cell monolayer was exposed to standardized cigarette smoke extract (CSE). The extent and effects of trans-epithelial allergen penetration were measured using 125I-labelled purified major respiratory allergens (rBet v 1, rPhl p 5 and rDer p 2) and histamine release experiments.

RESULTS

Exposure of cells to concentrations of CSE similar to those found in smokers induced the development of para-cellular gaps and a decrease in trans-epithelial resistance. CSE exposure induced a more than threefold increase in allergen penetration. Increased subepithelial allergen concentrations provoked a substantial augmentation of histamine release from sensitized basophils.

CONCLUSIONS

Our results indicate that cigarette smoke is a potent factor capable of reducing the barrier function of the respiratory epithelium for allergens and may contribute to increased allergic inflammation, exacerbation of allergic disease and boosting of IgE memory.

Microbiological study of cosmetic products during their use by consumers: health risk and efficacy of preservative systems

AIM

To evaluate the microbial contamination of 91 cosmetics (23 o/w emulsions, 47 tensiolytes, 21 aqueous pastes) in three different states of use (intact, in-use, ending product) and the protection efficacy of the preservative systems most frequently used in the analysed cosmetic formulations.

METHODS AND RESULTS

Total bacterial count, isolation and identification of pathogenic isolates were performed on the collected cosmetics. About 10.6% of tensiolytes (13.5% bath foam, 6.7% shampoo, 10% liquid soaps) were contaminated by Staphylococcus warneri, Staphylococcus epidermidis and Pseudomonas putida. The efficacy of the preservative systems of two cosmetic products, tested against standard micro-organisms (Staphylococcus aureus ATCC 4338 and Pseudomonas aeruginosa ATCC 9027) and two isolates from cosmetics in this study (S. epidermidis and P. putida), satisfied the Cosmetics, Toiletries, and Fragrance Association and Official Italian Pharmacopeia criteria, while only one tested cosmetic respected the Rapid Challenge Test criterion.

CONCLUSIONS

Contaminated cosmetic products are relatively uncommon, but some products, unable to suppress the growth of several micro-organisms, represent a potential health hazard.

SIGNIFICANCE AND IMPACT OF THE STUDY

The challenge test may be performed not only during the preparation of the preservative system in the intact cosmetics, but also be used to evaluate the protection efficacy during their use.

Flow cytometric evaluation ofVibrio parahaemolyticus adhesion inhibition to human epithelial cells

BACKGROUND

The present report demonstrates the usefulness of flow cytometry for a quantitative assessment of adhesion inhibition of a Vibrio parahaemolyticus strain to human epithelial cells to acquire more information about the nature of its adhesins.

METHODS

The inhibition of the adhesive process to Hep-2 was assayed by adding several monosaccharides to infected cells monolayers. The quantification of the adherent bacteria, labeled with a specific primary antibody plus a secondary fluorescein isothiocyanate-conjugated antibody, was performed by flow cytometry in comparison with light microscopy. The adherence was quantified in terms of the proportion of cells with adherent V. parahaemolyticus and as the mean of adherent bacteria per cell.

RESULTS

The adhesion showed a percentage of 98% with a mean fluorescence channel of 331 comparable to those obtained by light microscopy. The addition of monosaccharides resulted in a D-mannose and N-acetyl-galactosamine sensitive adherence. Even if this environmental strain also showed a mannose-sensitive cell-associated hemoagglutination that could mediate V. parahaemolyticus adherence, our results suggest that different sites for an irreversible adherence to host cell are involved.

CONCLUSIONS

Flow cytometry in combination with indirect immunofluorescence is an effective tool to investigate the adhesive process of bacteria to epithelial cells because it is more sensitive and reproducible than visual counting of bacteria performed in light microscopy.

‘In vivo’ studies on the pathophysiological mechanism of Vibrio parahaemolyticus TDH+—induced secretion

The thermostable direct haemolysin (TDH) is considered to be the major virulence factors of Vibrio parahaemolyticus; however, poor information is available about its mechanism of action. In our study we examined the capacity of two V. parahaemolyticus TDH-producers (strains 2067 and 3305) to induce fluid secretion in rat ileal loop and to reveal the role of calcium ions (Ca(2+)), calmodulin (CaM), and protein kinase C (PKC) in V. parahaemolyticus TDH(+)-induced fluid secretion. The results show that V. parahaemolyticus TDH(+) strains were able to induce secretion in small intestine; on the contrary, this ability was not evidenced in the V. parahaemolyticus TDH(-) strain used as negative control. The data suggest an enterotoxic activity of haemolysin. Calcium ionophore A23187 and 1-verapamil (calcium channel blocker), when injected alone, induced fluid accumulation in the control loops. A further increase in fluid accumulation (P<0.001) was noted when calcium ionophore was injected along with bacterial suspension of both TDH(+) strains and a significant decrease (P<0.001) in experimental loops when 1-verapamil was inoculated along with bacterial suspension. The other modulating agents increased fluid accumulation in both control and experimental loops, without significant differences with respect to the positive control. Our findings suggest that Ca(2+) appears to be an important messenger involved in the stimulation of intestinal secretion, contrary to PKC and calmodulin which do not appear to have any role.

Retention of virulence in viable but non-culturable halophilic Vibrio spp

The viable but non-culturable (VBNC) forms of two environmental strains of Vibrio alginolyticus 1 and Vibrio parahaemolyticus 66 and one strain of V. parahaemolyticus ATCC 43996 showing virulence characteristics (hemolysin production, adhesive and/or cytotoxic ability, in vivo enteropathogenicity) were obtained by culturing bacteria in a microcosm consisting of artificial sea water (ASW) and incubating at 5 degrees C with shaking. Every 2 days, culturability of the cells in the microcosm was monitored by spread plates on BHI agar and total count and the percentage of viable cells were determined by double staining with DAPI and CTC. When cell growth was not detectable (<0.1 CFU/ml), the population was considered non-culturable and, then, the VBNC forms were resuscitated in a murine model. For each strain, eight male Balb/C mice were intragastrically inoculated with 0.1 ml of concentrated ASW bacterial culture. Two mice from each group were sacrificed at 2, 4, 8, and 12 days after challenge for autopsy and re-isolation of the microorganisms from the intestinal tissue cultures. Isolation was obtained in 25% of the animals challenged with the VBNC V. alginolyticus strain, in 37.5% of those challenged with the VBNC V. parahaemolyticus strain of environmental origin and in 50% of the animals infected with VBNC V. parahaemolyticus ATCC 43996. The strains thus isolated were again subjected to biological assays to determine the retention of pathogenicity. The virulence characteristics that seemed to disappear after resuscitation in the mouse were subsequently reactivated by means of two consecutive passages of the strains in the rat ileal loop model. The results obtained indicate that VBNC forms of the strains examined can be resuscitated and retain their virulence properties.