1,340 research outputs found
Analysis of virulence factors in cases of enterococcal endocarditis.
No full textClin Microbiol Infect. 2004 Nov;10(11):1006-8.
Analysis of virulence factors in cases of enterococcal endocarditis.
Baldassarri L, Creti R, Arciola CR, Montanaro L, Venditti M, Di Rosa R.
Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanita, Rome, Italy. [email protected]
Eleven isolates of Enterococcus faecalis causing endocarditis were screened for possible virulence factors with PCR and phenotypic assays. The gene coding for the enterococcal surface protein (esp) was detected in one isolate only, and haemolysin was produced by two isolates. Aggregation substance, biofilm formation and gelatinase were present in seven, nine and eight isolates,
respectively. Predisposing factors, particularly hospitalisation and multiple antibiotic therapy, appeared to be more relevant to the development of enterococcal endocarditis following bloodstream infections than the pattern of virulence factors
Prevalence of cna, fnbA and fnbB adhesin genes among Staphylococcus aureus isolates from orthopedic infections associated to different types of implant.
No full textFEMS Microbiol Lett. 2005 May 1;246(1):81-6.
Prevalence of cna, fnbA and fnbB adhesin genes among Staphylococcus aureus isolates from orthopedic infections associated to different types of implant.
Arciola CR, Campoccia D, Gamberini S, Baldassarri L, Montanaro L.
Research Unit on Implant Infections, Rizzoli Orthopedic Institute, Via di Barbiano 1/10, 40136 Bologna, Italy. [email protected]
Here are reported data on virulence determinants of Staphylococcus aureus from orthopedic surgical infections, emphasizing on the genes encoding fibronectin (fnbA, fnbB) and collagen (cna) adhesins. 191 S. aureus strains from orthopedic
infections (53 from internal fixation devices, 29 external fixation devices, 15 knee arthroprostheses, 30 hip arthroprostheses, 45 surgical reconstruction and 19 non-associated to medical devices) were investigated for the presence of the genes of the collagen-binding protein Cna and of the two fibronectin-binding
proteins, FnbA and FnbB. 87 (46%) strains were found to be cna+ without significant variations across the different surgical categories considered. Conversely, the fnbA and the fnbB genes were almost always present in all surgical categories. The finding that, among the investigated adhesins, fibronectin-adhesins are present in the majority of the implant associated S. aureus clinical isolates encourages the development of strategies to specifically block the interaction of bacteria with matrix fibronectin by antagonist ligands
A multiplex PCR method for the detection of all five individual genes of ica locus in Staphylococcus epidermidis. A survey on 400 clinical isolates from prosthesis-associated infections
No full textJ Biomed Mater Res A.
A multiplex PCR method for the detection of all five individual genes of ica locus in Staphylococcus epidermidis. A survey on 400 clinical isolates from prosthesis-associated infections.
Arciola CR, Gamberini S, Campoccia D, Visai L, Speziale P, Baldassarri L, Montanaro L.
Research Unit on Implant Infections, Rizzoli Orthopedic Institute, Via di Barbiano, 1/10, 40136 Bologna, Italy.
[email protected]
In Staphylococcus epidermidis, ica locus encodes for the synthesis of a polysaccharide intercellular adhesin (slime or biofilm). A multiplex polymerase chain reaction (PCR) for the detection of the five individual genes of ica locus was developed, with the aim to probe the set of genes in a large collection of Staphylococcus epidermidis clinical isolates. Single representative fragments
for icaR, icaA, icaD, icaB, and icaC genes were selected. Multiplex PCR was applied to two reference Staphylococcus epidermidis strains [the non-biofilm-forming ATCC 12228 and the biofilm-forming ATCC 35984 (RP62A)] and to 400 clinical isolates of Staphylococcus epidermidis from orthopedic prosthesis associated infections. The gene profile was compared with the phenotypic biofilm-forming ability, evaluated by means of an optimized Congo red agar (CRA) plate test. Among the clinical isolates, 228 (57%) turned out completely ica positive and were biofilm producing. Among the 172 non-biofilm-forming strains (43%), 164 (41%) were completely ica negative and 8 strains (2%) harbored all five ica genes. The ica locus thus proves to be a cluster of strictly linked genes, without any evidence of single gene deletion.
(c) 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Evaluation of bacterial adhesion of Streptococcus mutans on dental restorative materials.
No full textBiomaterials. 2004 Aug;25(18):4457-63.
Evaluation of bacterial adhesion of Streptococcus mutans on dental restorative materials.
Montanaro L, Campoccia D, Rizzi S, Donati ME, Breschi L, Prati C, Arciola CR.
Research Laboratory on Biocompatibility of Implant Materials, Rizzoli
Orthopaedic Institute, and Experimental Pathology Department, University of Bologna, Italy. [email protected]
Bacterial adhesion to the surface of composite resins and other dental restorative materials is an important parameter in the aetiology of secondary caries formation. The aim of the present study was to investigate the adhesion of a Streptococcus mutans strain (ATCC 25175) on the surface of different restorative materials. The test materials examined included three flowable
composites (Filtek Flow, Tetric Flow, and Arabesk Flow), three microhybrid composites (Clearfil APX, Solitaire 2, and Z250), two glass-ionomers (Fuji IX, Fuji IX fast), a compomer (F2000), an ormocer (Admira), and a control reference material (tissue culture grade, surface treated polystyrene). The adhesion tests
were carried out in 24-well plates. Quantitative turbidimetric measurements were finally performed in order to indirectly evaluate the amount of bacteria retained on the material surface after in vitro exposure to the bacteria suspension. Under these conditions, with the exception of the Admira ormocer and the Fuji IX fast glass ionomer, which were found to be more adhesive, all the other material surfaces showed a similar susceptibility to bacterial adhesion, exhibiting values not significantly different than the reference polystyrene control. Furthermore, the release of fluoride from some of the test surfaces did not appear capable to reduce early bacterial adhesion
Constitutive Restrictions for Deformable Simple Media that are Heat Conducting and Electrically Polarizable
No full textWe present the constitutive restrictions for a deformable simple medium that is heat conducting, electrically polarizable and interacting with the electric field, either of elastic type or with a fading memory.
The used theory is an extension of the well known Green-Naghdi thermo-mechanical theories of continua, mainly devoted to thermoelastic bodies or rigid conductors. Hence the theory that is used here is based on an entropy balance law rather than an entropy imbalance, uses the notion of thermal displacement, and predicts
heat propagation by thermal waves at finite speed
Antibiotic resistance in exopolysaccharide-forming Staphylococcus epidermidis clinical isolates from orthopaedic implant infections
No full textBiomaterials. 2005 Nov;26(33):6530-5.
Antibiotic resistance in exopolysaccharide-forming Staphylococcus epidermidis clinical isolates from orthopaedic implant infections.
Arciola CR, Campoccia D, Gamberini S, Donati ME, Pirini V, Visai L, Speziale P, Montanaro L.
Research Unit on Implant Infections, Rizzoli Orthopaedic Institute, Via di Barbiano 1/10, 40136 Bologna, Italy. [email protected]
The opportunistic pathogen Staphylococcus epidermidis is able to produce biofilm and to frequently cause implant infections. In recent years, it has also exhibited an increasing antimicrobial drug resistance. Here, the resistance to a panel of 16 different antibiotics in 342 clinical strains of S. epidermidis from orthopaedic implant infections has been investigated. The isolates were pheno- and genotyped for extracellular polysaccharide production, relevant to staphylococcal biofilm formation, in order to ascertain possible associations with antibiotic resistance. Approximately 10% of the isolates were found to be sensitive to all screened antibiotics. In all, 37-38% were resistant to beta-lactams such as oxacillin and imipenem, while the resistance to penicillin, ampicillin, cefazolin, cefamandole, was consistently observed in over 80% of the
strains. Erythromycin- and clindamycin- resistant strains were approximately 41% and 16%, respectively. Of the isolates, 10% was resistant to chloramphenicol, 23% to sulfamethoxazole and 26% to ciprofloxacin. Resistance to vancomycin was never observed. Interestingly, exopolysaccharide-producing strains exhibited a significantly higher prevalence in the resistance to the four aminoglycosides (gentamicin, amikacin, netilmicin, tobramycin), to sulfamethoxazole and to ciprofloxacin with respect to non-producing isolates. Moreover, multiple resistance to antibiotics was more frequent among exopolysaccharide-forming strains
No genotoxicity of a new nickel-free stainless steel
No full textInt J Artif Organs. 2005 Jan;28(1):58-65.
No genotoxicity of a new nickel-free stainless steel.
Montanaro L, Cervellati M, Campoccia D, Prati C, Breschi L, Arciola CR.
Research Laboratory on Biocompatibility of Implant Materials, Rizzoli Orthopedic Institute, Bologna, Italy. [email protected]
Stainless steel is a metallic alloy largely employed in orthopedics,
maxillofacial surgery and orthodontic therapy. However, the presence in its composition of a high quantity of nickel, an agent known to trigger toxic, allergic and cancerogenous responses in humans, is cause of some concern. In this study, we have investigated the in vitro mutagenicity and genotoxicity of a
new nickel-free stainless steel, namely P558, in comparison to the conventional stainless steel AISI 316L. The cytogenetic effects were evaluated by studying the frequency of Sister Chromatid Exchanges (SCE) and chromosomal aberrations. Ames test was performed to detect the mutagenic activity. Both P558 and AISI
316L did not cause any significant increase in the average number of SCE and in chromosomal aberrations, either with or without metabolic activation. Furthermore, the Ames test showed that the extracts of both P558 and of AISI 316L are not mutagenic. Overall, these findings prove that P558 is devoid of genotoxicity and mutagenicity. The present results, together with other previous
interesting observations that P558 promotes osseointegration, suggest that this new nickel-free stainless steel can represent a better alternative to other conventional steel alloys
Dyskerin and cancer: more than telomerase. The defect in mRNA translation helps in explaining how a proliferative defect ends up in cancer.
No full text
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