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D Savoia

Publications and source records attributed to D Savoia.

At least 19 recordsLinked to original sources
PubMed2006

Burkholderia respiratory tract infections in Italian patients with cystic fibrosis: molecular characterization.

OBJECTIVES: To characterize by molecular techniques Burkholderia strains responsible for respiratory tract infections in cystic fibrosis (CF) patients (children and adults), to assign the Burkholderia cepacia complex (Bcc) isolates to a genomovar and to assess the presence of cblA and esmR genes in bacteria. Unique or sequential Burkholderia isolates (n=48) that had been collected from eight CF children and 17 adults over several (4-6) years were investigated; moreover 11 reference strains were analyzed. METHODS: The microorganisms were identified by using biochemical methods, genotyped by pulse field gel electrophoresis (PFGE) and random-amplified polymorphic DNA fingerprinting-PCR (RAPD-PCR), and assessed by PCR assays for the genomovar and cblA and esmR genes of Bcc. RESULTS: Among isolates 70.8% were identified as Bcc genomovar III-A; one child was infected by Burkholderia ambifaria and four adults were colonized with Burkholderia gladioli. The cblA gene was not detected in any of the isolates, while the esmR gene was detected in the 52.1% of the strains, all belonging to genomovar III-A. CONCLUSION: Molecular analysis of strains revealed in CF patients a colonization with a persistent Burkholderia flora with strains of one genotype. The prevalence of Bcc of genomovar III-A in the two categories of patients and of B. gladioli in four adults demonstrated that transmission may have occurred between subjects. Moreover the B. ambifaria infection demonstrated in a child may be environmentally derived.

Adult↗
PubMed2005

Transmission of Burkholderia cepacia complex: evidence for new epidemic clones infecting cystic fibrosis patients in Italy.

To analyze national prevalence, genomovar distribution, and epidemiology of the Burkholderia cepacia complex in Italy, 225 putative B. cepacia complex isolates were obtained from 225 cystic fibrosis (CF) patients attending 18 CF centers. The genomovar status of these isolates was determined by a polyphasic approach, which included whole-cell protein electrophoresis and recA restriction fragment length polymorphism (RFLP) analysis. Two approaches were used to genotype B. cepacia complex isolates: BOX-PCR fingerprinting and pulsed-field gel electrophoresis (PFGE) of genomic macrorestriction fragments. A total of 208 (92%) of 225 isolates belonged to the B. cepacia complex, with Burkholderia cenocepacia as the most prevalent species (61.1%). Clones delineated by PFGE were predominantly linked to a single center; in contrast, BOX-PCR clones were composed of isolates collected either from the same center or from different CF centers and comprised multiple PFGE clusters. Three BOX-PCR clones appeared of special interest. One clone was composed of 17 B. cenocepacia isolates belonging to recA RFLP type H. These isolates were collected from six centers and represented three PFGE clusters. The presence of insertion sequence IS 1363 in all isolates and the comparison with PHDC reference isolates identified this clone as PHDC, an epidemic clone prominent in North American CF patients. The second clone included 22 isolates from eight centers and belonged to recA RFLP type AT. The genomovar status of strains with the latter RFLP type is not known. Most of these isolates belonged to four different PFGE clusters. Finally, a third clone comprised nine B. pyrrocinia isolates belonging to recA RFLP type Se 13. They represented three PFGE clusters and were collected in three CF centers.

Bacterial Typing Techniques↗
PubMed2001

Interaction of Bartonella henselae with the murine macrophage cell line J774: infection and proinflammatory response.

Bartonella henselae is the causative agent of cat scratch disease (CSD), a self-limiting condition characterized by a subacute regional lymphadenopathy that may develop into disseminated bartonellosis in immunocompromised subjects. Mice experimentally infected with B. henselae display typical liver and spleen granulomas rich in T cells and macrophages. So far there are no data on the interaction between bartonellae and macrophages. In order to clarify this topic, we investigated the interaction of B. henselae with J774, a mouse macrophage cell line. Analysis of bacterial uptake by functional assays and transmission electron microscopy indicates that bartonellae can enter and survive inside J774. Entry occurred within 30 min postinfection and reached a plateau at 160 min. Infection of J774 was followed by a dose-dependent release of the proinflammatory cytokines tumor necrosis factor alpha, interleukin 1beta (IL-1beta), and IL-6. Bartonellae persisted intracellularly without loss of viability for at least 8 h, and their number slightly decreased 24 h postinfection. Gamma interferon (IFN-gamma) treatment of J774 significantly decreased the number of recoverable bacteria at 8 and 24 h. This enhancement of macrophage bactericidal activity was associated with nitric oxide (NO) release and was prevented by the addition of the competitive inhibitor of NO synthesis N(G)-monomethyl L-arginine. These findings suggest that IFN-gamma-mediated activation of macrophages may be important for the clearing of B. henselae infection and that anti-B. henselae microbicidal activity of IFN-gamma-activated macrophages is mediated to a large extent by NO production.

Animals↗
PubMed2001

Genetic diversity of Pneumocystis carinii isolated from human immunodeficiency virus-positive patients in Turin, Italy.

By DNA sequence analysis we identified two new strain types and five novel sporadic variations among 25 isolates of Pneumocystis carinii f. sp. hominis obtained from 19 human immunodeficiency virus-positive patients. Of these, 13 were infected with a single strain and 6 were coinfected. Fifteen different combination types were identified among the 18 strains for which complete molecular typing was accomplished.

AIDS-Related Opportunistic Infections↗
PubMed2000

In vitro activity of propolis against Streptococcus pyogenes.

Propolis, a multifunctional substance used by bees to maintain the safety of their hives, is popular for its therapeutic potential against some micro-organisms. Ethanolic extracts of two propolis specimens, collected from different areas within a region in the north-west of Italy, were examined to evaluate their antimicrobial activity against 46 Streptococcus pyogenes strains. By both agar dilution and agar diffusion methods, the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were </= 234 microg ml-1, corresponding to a one in 512 dilution of the 12% (w/v) extracts. One of the two propolis samples was more active and this extract was shown to be richer in the flavonoids pinocembrin and galangin using HPLC. Therefore, with a simple microbiological assay technique, in particular the agar dilution method, it was possible to standardize the analysis of propolis samples to identify the quality parameters of this natural product before use for medical treatment.

Child↗
PubMed2000

Streptococcus pyogenes collected in Torino (northwest Italy) between 1983 and 1998: survey of macrolide resistance and trend of genotype by RAPD.

We surveyed macrolide resistance in 1,086 isolates of Streptococcus pyogenes, collected between 1983 and 1998, from throat swabs of children with untreated pharyngotonsillitis living in Torino (northwest Italy). In 1983 and 1985, the frequency of erythromycin resistance was 10%, and from 1990 to 1992 it was 4%. However, it rose to 16.6% in 1994 and reached 51% in 1996 before decreasing to 38.5% in 1998. Characterization of the phenotype of resistant isolates revealed the prevalence of constitutive resistance (CR) in 1996, whereas the M phenotype, characterized by resistance to 14- and 15-membered macrolides with susceptibility to clindamycin and streptogramin B, prevailed in 1998. Moreover, in 1997 we observed an increase in the frequency of autoagglutinating bacteria and, in 1998, of OF-negative S. pyogenes. Meanwhile, penicillin tolerance, assessed in the isolates collected from 1990 to 1996, decreased and disappeared. Random amplification of polymorphic DNA (RAPD) was used to obtain the genomic profile of 32 S. pyogenes strains. Four main DNA profiles were demonstrated, generally related to the macrolide-resistance phenotype and for the major part to the T serotype. These results indicate that RAPD is reliable as a first screening method in the epidemiological characterization of resistant S. pyogenes.

Anti-Bacterial Agents↗
PubMed2000

Macrolide resistance in group A streptococci.

Two hundred and twenty one Streptococcus pyogenes isolates collected from throat swabs of untreated children with uncomplicated pharyngotonsillitis living in two centres situated in the north of Italy were tested to evaluate their macrolide resistance phenotype. Isolates were also typed for T protein and assayed for opacity factor (OF) and protease production. Resistance to macrolides was found to be similar in the two centres. Fifty-one point two per cent of Torino strains and 43.5% of Pinerolo strains were not inhibited by erythromycin. Resistant strains belonged to one of three phenotypes: CR, constitutive resistance (37.9 and 42.5% in Torino and Pinerolo, respectively); IR, inducible resistance (40.9 and 17. 5%); NR, new resistance phenotype (21.2 and 40%). All the resistant and some of the susceptible strains were analysed by pulsed-field gel electrophoresis and genomic patterns were defined on the basis of band size and number. Five DNA profiles were found among erythromycin-resistant strains: three patterns characterized the NR resistance phenotype and one each the IR and CR phenotypes. The distribution of resistant strains according to their genomic patterns appears to be related to the resistance phenotype and only in some cases to the T serotype of bacteria. We conclude that the S. pyogenes strains analysed are genetically heterogeneous and therefore the high rate of erythromycin resistance observed is not caused by the spread of a single clone nor is it related to a particular serotype.

Anti-Bacterial Agents↗
PubMed1998

Interleukin-15 activates proinflammatory and antimicrobial functions in polymorphonuclear cells.

Interleukin-15 (IL-15) is a recently discovered cytokine produced by a wide range of different cell types including fibroblasts, keratinocytes, endothelial cells, and macrophages in response to lipopolysaccharide or microbial infection. This suggests that IL-15 may play a crucial role in the activation of phagocytic cells against pathogens. We studied polymorphonuclear leukocyte (PMN) activation by IL-15, evaluated as enhancement of PMN anti-Candida activity as well as IL-8 production, following stimulation with the cytokine. The PMN response to IL-15 depends on binding to the IL-15 receptor. Our experiments show that binding of a biotinylated human IL-15-immunoglobulin G2b IgG2b fusion protein was competed by the addition of human recombinant IL-15 (rIL-15) or of human rIL-2, suggesting that IL-15 binding to PMN might involve the IL-2Rbeta and IL-2Rgamma chains, which have been shown to be constitutively expressed by PMN. In addition, we show by reverse transcription-PCR and by flow cytometry with a specific anti-IL-15Ralpha chain monoclonal antibody that PMN express the IL-15Ralpha chain at the mRNA and protein levels. Incubation with IL-15 activated PMN to secrete the chemotactic factor IL-8, and the amount secreted was increased by costimulation with heat-inactivated Candida albicans. In addition, IL-15 primed the metabolic burst of PMN in response to formyl-methionyl-leucyl-phenylalanine but was not sufficient to trigger the respiratory burst or to increase the production of superoxide in PMN exposed to C. albicans. IL-15 also increased the ability of PMN to phagocytose heat-killed C. albicans organisms in a dose-dependent manner, without opsonization by antibodies or complement-derived products. In the same concentration range, IL-15 was as effective as gamma interferon (IFN-gamma) and IL-2 in increasing the C. albicans growth-inhibitory activity of PMN. Taken together, these results suggest that IL-15 is a potent stimulant of both proinflammatory and antifungal activities of PMN, activating several antimicrobial functions of PMN involved in the cellular response against C. albicans.

Candida albicans↗
PubMed1997

Detection of Pneumocystis carinii by DNA amplification in human immunodeficiency virus-positive patients.

The opportunistic pathogen Pneumocystis carinii (PC) is a frequent cause of a life-threatening pneumonia in human immunodeficiency virus (HIV)-infected individuals and in other immunocompromised hosts. Specimens obtained from 128 bronchoalveolar lavage (BAL) fluid samples from 123 HIV-positive patients with pulmonary disease and undergoing a diagnostic bronchoscopy were evaluated to detect this organism. We have developed a rapid DNA extraction procedure for nested polymerase chain reaction (PCR) using two sets of primers (pAZ102-E, pAZ102-H and P1 = 5'-CTAGGATATAGCTGGTTTTC-3' and P2 = 5'-TCGACTATCTAGCTTATCGC-3'). The results were compared using cytological techniques (direct wet mount, Giemsa, toluidine blue O) and related to the clinical follow-up of patients. The nested PCR had a 91% sensitivity and a 93% specificity. The effect of chemoprophylaxis and the evaluation of the follow-up of patients are discussed. Nested PCR may represent an important additional tool, along with current cytological methods, for the detection of P. carinii; however, at present it cannot replace routine microbiological methods more simple and less expensive.

AIDS-Related Opportunistic Infections↗
PubMed1997

[Recurrent urinary tract infections. Biological suppositions and clinical treatment with thymopentin].

BACKGROUND: Urinary tract infections (UTI) are a common usual pathological event. They relapse often due to the periurethral colonization of microorganisms from the intestinal bacterial flora. They also constitute an important and considerable social and clinical problem. The absence of inducing organic conditions or an infective focus at the base of the pathogenetic mechanism suggests the existence of alterations of the immune response of the subject. MATERIALS AND METHODS: In this work we wanted to verify if, in those subjects with relapsing UTI (more than four events every year) cure with "biological" response modifiers, particularly "thymopentin", meaningfully reduced the number of events. RESULTS: The results obtained confirm that for those cases in which the chemo-antibiotic therapy did not have the expected results, it is rational to support it with an immune-modulating drug (thymopentin). In fact the post-therapy reduction of UTI observed during two years of follow-up is statistically significant when compared to the average of UTI before therapy. CONCLUSIONS: The "cost-benefits" analysis should prove to be a saving in favour of the use of thymopentin, taking into consideration the reduction of chemo-antibiotics consumption and the lower number of working hours lost every year.

Adjuvants, Immunologic↗
PubMed1996

Leishmania major: infection of human monocytes induces expression of IL-8 and MCAF.

Leishmania major, the causative agent of cutaneous leishmaniasis, is an intracellular parasite of monocytic cells. Leishmania lesions are characterized by recruitment of neutrophils, eosinophils, and blood monocytes. To clarify the mechanism of this cellular influx we examined the expression of IL-8 and MCAF, cytokines chemotactic for neutrophils and monocytes, respectively, in human monocytes infected by L. major. Supernatants of monocytes infected with L. major had chemotactic activity for neutrophils and monocytes that was neutralized by anti-IL-8 and anti-MCAF antibodies. Both IL-8 and MCAF mRNAs were induced within 1 hr of infection. Furthermore we showed that infection of monocytes with L. major induces IL-8 and MCAF but not the proinflammatory cytokines IL-1 beta and TNF alpha. These data suggest that the expression of chemokines may contribute to the cellular recruitment in Leishmania lesions.

Animals↗
PubMed1996

Pseudomonas aeruginosa clinical isolates: serotypes, resistance phenotypes and plasmid profiles.

78 Pseudomonas aeruginosa strains were isolated from the respiratory tract of 56 patients, 15 of which were affected by cystic fibrosis (CF). The epidemiological typing scheme was based on serotyping, antibiotic resistance pattern and plasmid DNA profile. All strains (except 2 mucoid strains) were typed using a rapid slide O-agglutination technique. Most common serotypes in both group were 0:1, 0:10 and 0:6. Moreover we observed a correlation among 0:12 serotype and CF patients. Plasmid DNA analysis showed that 45.2% (on average) of strains isolated from patients with and w/o CF harboured 1-3 plasmids ranging in size from 1 to 15 Md. Plasmid prevalence was higher in strains isolated from CF patients in specimens collected after antibiotic therapy. A correlation was found between 1 and 1.9 Md plasmids and resistance to aminoglycosides. Our results indicate that the analysis of antibiotic resistance phenotypes combined with plasmid analysis may be useful, in association to serotyping, to characterize the circulation of P. aeruginosa strains and the spread of resistance in these bacteria.

Cystic Fibrosis↗
PubMed1996

Evaluation of the immune response in visceral leishmaniasis.

Detection of parasites in culture or by microscopy is still necessary to make diagnosis of visceral leishmaniasis (VL). Serological methods still need assessment, as they are quick but not very sensitive, especially in immunosuppressed subjects. This paper compares the results obtained with three serological methods (indirect immunofluorescence test (IFAT), direct agglutination test (DAT), and enzyme-linked immunosorbent assay (ELISA) and the specific cell-mediated immune response, evaluated as proliferation and IFN-gamma production by peripheral blood lymphocytes (PBL) following stimulation with heat-killed L. infantum promastigotes. PBL and sera were obtained from 10 healthy donors, 3 VL patients in acute phase, and 3 patients recovering after two glucantim treatment courses. No false positive results were observed with the serological methods. IFAT can be considered the most sensitive and best suited for follow-up, as it allowed a good discrimination between the acute and remission phase. DAT did not discriminate between healthy donors and remission-phase patients, whereas ELISA is unsuited for follow-up, as it did not show any significant difference between remission- and acute-phase patients. Assessment of the cellular response is not recommended for making a diagnosis, because false positive results are frequent. However, a strong cellular response in a patient stands for a successful treatment. IFN-gamma titration is preferable to the proliferation test, because it gives earlier results and does not require the use of radioactive isotopes.

Agglutination Tests↗
PubMed1996

Protective role of the pefloxacin-IFN-gamma association in Leishmania major-infected mice.

Four groups of female Balb/c mice were inoculated in the left hind footpad with 30 microliters of RPMI 1640 medium containing 10(7) Leishmania major amastigotes/ml. One group was injected sc with 200 microliters of RPMI 1640 containing 180 micrograms of pefloxacin for 20 days, a second group with the same amount of medium containing 100 units of recombinant murine interferon gamma (rmIFN-gamma). The third group was treated with the association, while the fourth group received plain medium in an identical regimen. Pefloxacin or IFN-gamma significantly decreased the size of primary lesions, while their association was significantly more efficient in this respect, in reducing the incidence of metastatic lesions, and in clearing parasites from the spleen. We also investigated the effect of pefloxacin on the activation of mouse spleen cells by Concanavalin A (Con A) in vitro, without detecting any interference on the proliferative response or IFN-gamma production.

Animals↗
PubMed1996

A one-year survey of respiratory and urinary pathogens and their antimicrobial susceptibility.

A one-year (1993) survey of the distribution of pathogens causing respiratory and urinary infections and their antimicrobial susceptibility was performed. The most common bacteria isolated from the lower respiratory tract of patients in a district general hospital were Pseudomonas aeruginosa (35.9%) and Staphylococcus aureus (21.4%). About half of the Pseudomonas strains revealed a resistance to imipenem and gentamicin, whereas almost all Staphylococcus strains were resistant to penicillin G. The most common isolates from urine of in and out-patients were Escherichia coli (32.3% and 39.8%) and Enterococcus faecalis (16.6% and 14.2%). Escherichia coli strains were largely susceptible to almost all chemoantibiotics tested, whereas Enterococcus faecalis demonstrated a high resistance pattern. Pseudomonas aeruginosa isolated from urine were more sensitive to chemoantibiotics than respiratory strains and the susceptibility of Staphylococcus aureus isolated from hospitalized or out-patients was different. A periodic monitoring system devised to give information about the circulation of bacteria and the chemoantibiotic resistance in a local context would be useful to assess the local trends and select drugs for therapy.

Drug Resistance, Microbial↗
PubMed1996

[Protozoan infection (Blastocystis hominis) concomitant with Pseudomonas sp. peritonitis in continuous ambulatory peritoneal dialysis (CAPD)].

Case-report of protozoal infection (Blastocystis bominis) during Pseudomonas peritonitis in male patient with intestinal diverticulosis on continuous ambulatory peritoneal dialysis (CAPD) treatment for chronic renal failure (CRF). Microscopic morphology and cultural characteristics are summarized from current literature. Photographic images in phase contrast from fresh-observation of faeces and peritoneal fluid are reported. Although other Protozoa (e.g. Acanthamoeba free-living) have already been found in dialysis fluid, this is the first case, referred in literature, of Blastocystis bominis infection in CAPD patients. Some pathogenetic hypothesis are done involving Blastocystis bominis in peritoneal infection, especially in immunodepressed patients like dialysed ones. Although many chemotherapeutics are provided for this protozoiasis during enteritis, in our case no supplement was required except specific antibiotic therapy for Pseudomonas infection. Symbion or pathogen? Is now-a-day the question which troubles parasitologists. Systemic research of Protozoa in dialysed patients is anyhow advisable.

Animals↗
PubMed1996

Aspecific adherence and cytotoxicity of Escherichia coli strains.

Two groups of Escherichia coli were assayed to evaluate hydrophobic characters and the secretion of enzymes and cytotoxic factors. Group 1 included strains isolated from the urine of patients with lower urinary tract infection (UTI) and group 2 included strains from the same sample of asymptomatic subjects. The bacterial hydrophobicity was similar in the two groups and related to their adhesion to plastic surfaces, while both cytotoxic factors (demonstrated using a microscopic and a spectrophotometric technique) and hydrolysing enymes were secreted more by the first group of E. coli. The superior production of these factors may be important in the pathogenesis and in the development of symptomatic UTI infections.

Adult↗