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Luigi Chiarini

Publications and source records attributed to Luigi Chiarini.

12 recordsLinked to original sources
PubMed2006

Burkholderia cepacia complex species: health hazards and biotechnological potential.

The Burkholderia cepacia complex is a group of nine closely related bacterial species that have useful properties in the natural environment as plant pest antagonists, plant growth promoters and degradative agents of toxic substances. Because these species are human opportunistic pathogens, especially in cystic fibrosis patients, biotechnological applications that involve environmental releases have been severely restricted. Recent progress in understanding the taxonomy, epidemiology and ecology of the B. cepacia complex species has unravelled considerable variability in their pathogenicity and ecological properties, which has set the basis for a reassessment of the risk posed by individual species to human health.

Burkholderia cepacia complex↗
PubMed2006

Two techniques for the preparation of cell-scaffold constructs suitable for sinus augmentation: steps into clinical application.

The objective of this clinical trial was the analysis of 2 methods for engineering of autologous bone grafts for maxillary sinus augmentation with secondary implant placement. Group 1 (8 patients, 12 sinuses): cells of mandibular periosteum were cultured in a good manufacturing practice laboratory (2 weeks) with autologous serum and then transferred onto a collagen matrix. After another week, these composites were transplanted into the sinuses. In group 2A (2 patients, 3 sinuses), cells of maxillary bone were cultivated with autologous serum for 2 weeks, seeded onto natural bone mineral (NBM, diameter [Ø] = 8 mm) blocks, and cultivated for another 1.5 months. These composites were transplanted into the sinuses. Group 2B (control, 3 patients, 5 sinuses) received NBM blocks alone. In the course of implant placement 6 (group 1) and 8 (group 2) months later, core biopsy were taken. Clinical follow-up period was 1 to 2.5 years in group 1 and approximately 7 years in groups 2A and 2B. New vital bone was found in all cases at median densities of 38% (n = 12) in group 1, 32% in group 2A (n = 3), and 25% in group 2B (n = 5). Differences between group 1 and 2B as well as 2A and 2B were statistically significant ( p = 0.025). No adverse effects were seen. All methods described were capable of creating new bone tissue with sufficient stability for successful implant placement.

Adult↗
PubMed2005

Metabolic profiling of Burkholderia cenocepacia, Burkholderia ambifaria, and Burkholderia pyrrocinia isolates from maize rhizosphere.

Burkholderia cenocepacia, Burkholderia ambifaria, and Burkholderia pyrrocinia are the Burkholderia cepacia complex (Bcc) species most frequently associated with roots of crop plants. To investigate the ecophysiological diversity of these species, metabolic profiling of maize rhizosphere isolates was carried out by means of the Biolog system, using GN2 and SFN2 plates and different parameters related to optical density (OD). The metabolic profiles produced by the SFN2 and GN2 plates were identical, but the SFN2's narrower range of OD values and significantly longer reaction times made these plates less suitable for differentiation of isolates. Principal component analysis of maximum OD (ODM) and maximum substrate oxidation rate (muM) data generated by GN2 plates allowed the selection of a reduced number of carbon sources. Statistical analysis of ODM values highlighted marked differences between the metabolic profiles of B. cenocepacia and B. ambifaria, whereas metabolic profiles of B. pyrrocinia clustered very often with those of B. cenocepacia. Analysis of the mu(M) parameter resulted in a slightly lower differentiation among the three Bcc species and a higher metabolic diversity within the single species, in particular within B. cenocepacia. Finally, B. cenocepacia and B. pyrrocinia showed generally higher oxidation rates than B. ambifaria on those GN2 substrates that commonly occur in maize root exudates.

Burkholderia cepacia↗
PubMed2005

Effect of Fusarium verticillioides on maize-root-associated Burkholderia cenocepacia populations.

Burkholderia cepacia complex (Bcc) bacteria are naturally present in the rhizosphere of several crop plants and have been found to antagonize a wide range of important plant pathogens. In this study, we evaluated the effect of the pathogenic fungus Fusarium verticillioides on Bcc populations recovered from the roots of Zea mays plants. Maize plants were cultivated under greenhouse conditions and bacterial colonies were randomly isolated from distinct root portions of Fusarium-treated and control plants. We obtained a total of 120 Bcc isolates which all belonged to the species Burkholderia cenocepacia, a species of the Bcc widely distributed in natural habitats such as the rhizosphere of several crop plants. Results obtained revealed that the presence of the plant pathogen F. verticillioides had an effect at the root colonization level of B. cenocepacia populations, since an increase in indigenous B. cenocepacia bacteria was found in the rhizospheres of maize plants grown in infested soil, compared to the rhizospheres of control plants. The analysis of diversity indices as well as the investigation of genetic polymorphism of B. cenocepacia strains, isolated from Fusarium-treated and control root portions, revealed greater genetic variability in the presence of F. verticillioides, especially in the terminal root system portion. Finally, all B. cenocepacia isolates were also tested for in vitro inhibition of F. verticillioides growth as a functional property. Our results revealed that all B. cenocepacia isolates were able to restrict in vitro fungal growth, suggesting that there was no relationship between genetic polymorphism and biocontrol traits.

Antibiosis↗
PubMed2005

Efficacy of species-specific recA PCR tests in the identification of Burkholderia cepacia complex environmental isolates.

In this study, we evaluated if recA species-specific PCR assays could be successfully applied to identify environmental isolates of the widespread Burkholderia cepacia complex (Bcc) species. A total of 729 Bcc rhizosphere isolates collected in different samplings were assigned to the species B. cepacia genomovar I (61), B. cenocepacia recA lineage IIIB (514), B. ambifaria (124) and B. pyrrocinia (30), by means of recA (RFLP) analysis, and PCR tests were performed to assess sensitivity and specificity of recA species-specific primers pairs. B. cepacia genomovar I specific primers produced the expected amplicon with all isolates of the corresponding species (sensitivity, 100%), and cross-reacted with all B. pyrrocinia isolates. On the contrary, B. cenocepacia IIIB primers did not give the expected amplicon in 164 B. cenocepacia IIIB isolates (sensitivity, 68.1%), and isolates of distinct populations showed different sensitivity. B. ambifaria primers failed to amplify a recA-specific fragment only in a few isolates of this species (sensitivity, 93.5%). The absence of specific amplification in a high number of B. cenocepacia rhizosphere isolates indicates that recA specific PCR assays can lead to an underestimation of environmental microorganisms belonging to this bacterial species.

Bacterial Proteins↗
PubMed2005

Detection of cultured and uncultured Burkholderia cepacia complex bacteria naturally occurring in the maize rhizosphere.

The species composition of a Burkholderia cepacia complex population naturally occurring in the maize rhizosphere was investigated by using both culture-dependent and culture-independent methods. B. cepacia complex isolates were recovered from maize root slurry on the two selective media Pseudomonas cepacia azelaic acid tryptamine (PCAT) and trypan blue tetracycline (TB-T) and subjected to identification by a combination of restriction fragment length polymorphism (RFLP) analysis and species-specific polymerase chain reaction (PCR) tests of the recA gene. DNA extracted directly from root slurry was examined by means of nested PCR to amplify recA gene with species-specific B. cepacia complex primers and to obtain a library of PCR amplified recA genes. Using the culture-dependent method the species Burkholderia cepacia, Burkholderia cenocepacia, Burkholderia ambifaria and Burkholderia pyrrocinia were identified, whereas using the culture-independent method also the species Burkholderia vietnamiensis was detected. The latter method also allowed us to highlight a higher diversity within the B. cenocepacia species. In fact, by using the culture-independent method the species B. cenocepacia recA lineages IIIA and IIID besides B. cenocepacia recA lineage IIIB were detected. Moreover, higher heterogeneity of recA RFLP patterns was observed among clones assigned to the species B. cenocepacia than among B. cenocepacia isolates from selective media.

Base Sequence↗
PubMed2004

Exopolysaccharides produced by Burkholderia cenocepacia recA lineages IIIA and IIIB.

Clinical and environmental strains of Burkholderia cenocepacia belonging to the recA lineages IIIA and IIIB were examined for exopolysaccharide (EPS) production. The exopolysaccharides structure was determined using mainly gas chromatography coupled to mass spectrometry and NMR spectroscopy. All the strains produced Cepacian, a highly branched polysaccharide constituted of a heptasaccharide repeating unit, composed of one rhamnose, one glucose, one glucuronic acid, one mannose and three galactose residues. This polymer is the most common exopolysaccharide produced by strains of the Burkholderia cepacia (Bcc) complex. One clinical strain produced also another polysaccharide constituted of three galactose units and one 3-deoxy-D-manno-2-octulosonic acid residues, a polymer that was previously isolated from two strains of B. cepacia genomovar I and B. cenocepacia IIIA.

Burkholderia cepacia↗
PubMed2004

Cranioplasty using acrylic material: a new technical procedure.

AIM: Today, cranioplasty is performed using different procedures. Numerous materials may be used to reconstruct the cranial vault including autologous bone and different types of synthetic resins. When plastic materials are used, the main requirement for an effective cranioplasty is the preoperative shaping of the implant to fit the bony defect precisely. In this paper, experience with a new method for cranioplasty using an acrylic cranial implant is presented. MATERIAL AND METHODS: In this new technical procedure an acrylic implant, precisely shaped to the defect, is fabricated preoperatively using CT data. The study consists of 15 cases in whom cranioplasty was performed using this method. In all these, reconstruction was at least 3 months after the initial operation that lead to the cranial bony defect. RESULTS: No major complications occurred and the final functional and aesthetic results were good in all cases. The acrylic implant manufacture does not require the use of complex computer interface software or high-tech equipment, but involves simple, cheap, repeatable processes.

Adult↗
PubMed2004

Epidemiology and clinical course of Burkholderia cepacia complex infections, particularly those caused by different Burkholderia cenocepacia strains, among patients attending an Italian Cystic Fibrosis Center.

In this study, the epidemiology of Burkholderia cepacia complex (Bcc) recovered from the sputum of 75 patients attending the Genoa Cystic Fibrosis (CF) Center at the Gaslini Children's Hospital (Genoa, Italy) was investigated, and the clinical course of the CF patients infected with the different species and genomovars of Bcc was evaluated. All isolates were analyzed for genomovar status by recA gene polymorphism and subsequently random amplified polymorphic DNA fingerprinting. Burkholderia cenocepacia is the predominant species recovered from the CF patients infected with Bcc at the Genoa CF Center. Of the other eight species comprising the Bcc, only a few isolates belonging to B. cepacia genomovar I, Burkholderia stabilis, and Burkholderia pyrrocinia were found. Of the four recA lineages of B. cenocepacia, most patients were infected by epidemic strains belonging to lineages IIIA and IIID, whereas only a few patients harbored IIIB strains. Patient-to-patient spread of Bcc among CF patients was mostly associated with B. cenocepacia, in particular with strains belonging to recA lineages IIIA and IIID. The mortality of CF patients infected with Bcc at the Genoa CF Center was significantly higher than mortality among CF patients not infected with Bcc. All of the deaths were associated with the presence of B. cenocepacia, except the case of a patient infected with B. cepacia genomovar I. Within B. cenocepacia, infection with epidemic strains belonging to lineages IIIA and IIID was associated with higher rates of mortality than was infection with lineage IIIB strains. No significant differences in lung function, body weight, and mortality rate were observed between patients infected with epidemic strains belonging to either B. cenocepacia IIIA or B. cenocepacia IIID.

Adolescent↗
PubMed2002

Effects of two different application methods of Burkholderia ambifaria MCI 7 on plant growth and rhizospheric bacterial diversity.

In order to acquire a better understanding of the effects of the different delivery modes of bacterial inoculants on plant growth and on the community structure of rhizosphere bacterial populations, Burkholderia ambifaria MCI 7 (formerly B. cepacia MCI 7) was inoculated into the rhizosphere of maize plants by either seed adhesion or incorporation into soil. Plant growth was evaluated at different inoculum concentrations. The community structure of rhizosphere bacterial populations was evaluated by analysing the restriction patterns of the DNA coding for 16S rRNA amplified by polymerase chain reaction (PCR) (ARDRA) of 745 bacterial isolates. A number of diversity indices (richness, Shannon diversity, evenness and mean genetic distance) were calculated for each bacterial population isolated from control and treated plants according to the concept of the r/K strategy. Moreover, the analysis of molecular variance (AMOVA) method was applied to estimate the genetic differences among the various bacterial populations. Our results showed that the method of application can be an essential element in determining the effects of the inoculant on plant growth. In fact, when applied as a maize seed treatment, B. ambifaria MCI 7 promoted plant growth significantly; on the contrary, when incorporated into soil, the same strain reduced plant growth markedly. As far as the bacterial community structure is concerned, B. ambifaria MCI 7 affected the indigenous microflora of treated plants according to the application method: seed treatment brought about an abrupt decrease in bacterial diversity, whereas incorporation into soil increased bacterial diversity. Moreover, changes in bacterial diversity were limited to r-strategist bacteria. In conclusion, B. ambifaria MCI 7 can act as both a plant growth-promoting rhizobacterium and a deleterious rhizobacterium depending on the inoculation method.

Burkholderia↗
PubMed2002

Burkholderia cepacia complex bacteria from clinical and environmental sources in Italy: genomovar status and distribution of traits related to virulence and transmissibility.

Sixty-eight Burkholderia cepacia complex isolates recovered from the sputum of 53 cystic fibrosis patients and 75 isolates collected from the maize rhizosphere were compared to each other to assess their genomovar status as well as some traits related to virulence such as antibiotic susceptibility, proteolytic and hemolytic activities, and transmissibility, in which transmissibility is determined by detection of the esmR and cblA genes. Among the clinical isolates, B. cepacia genomovar III comprised the majority of isolates examined and only a very few isolates were assigned to B. cepacia genomovar I, B. stabilis, and B. pyrrocinia; among the environmental isolates a prevalence of B. cepacia genomovar III and B. ambifaria was observed, whereas few environmental isolates belonging to B. cepacia genomovar I and B. pyrrocinia were found. Antibiotic resistance analysis revealed a certain degree of differentiation between clinical and environmental isolates. Proteolytic activity and onion tissue maceration ability were found to be spread equally among both clinical and environmental isolates, whereas larger percentages of environmental isolates than clinical isolates had hemolytic activity. The esmR gene was found exclusively among isolates belonging to B. cepacia genomovar III, with a marked prevalence in clinical isolates, whereas only one clinical isolate belonging to B. cepacia genomovar III was found to bear the cblA gene. In conclusion, the results of the present study show that the species compositions of the clinical and environmental B. cepacia complex populations examined are quite different and that some of the candidate determinants related to virulence and transmissibility are not confined solely to clinical isolates but are also spread among environmental isolates belonging to different species of the B. cepacia complex.

Burkholderia cepacia↗