1,721,013 research outputs found
The endothelium at the interface between tissues and Staphylococcus aureus in the bloodstream
No full textStaphylococcus aureus is a major human pathogen. It can cause many types of infections, in particular bacteremia, which frequently leads to infective endocarditis, osteomyelitis, sepsis, and other debilitating diseases. The development of secondary infections is based on the bacterium's ability to associate with endothelial cells lining blood vessels. The success of endothelial colonization and infection by S. aureus relies on its ability to express a wide array of cell wall-anchored and secreted virulence factors. Establishment of endothelial infection by the pathogen is a multistep process involving adhesion, invasion, extravasation, and dissemination of the bacterium into surrounding tissues. The process is dependent on the type of endothelium in different organs (tissues) and pathogenetic potential of the individual strains. In this review, we report an update on the organization of the endothelium in the vessels, the structure and function of the virulence factors of S. aureus, and the several aspects of bacteria-endothelial cell interactions. After these sections, we will discuss recent advances in understanding the specific mechanisms of infections that develop in the heart, bone and joints, lung, and brain. Finally, we describe how neutrophils bind to endothelial cells, migrate to the site of infection to kill bacteria in the tissues, and how staphylococci counteract neutrophils' actions. Knowledge of the molecular details of S. aureus-endothelial cell interactions will promote the development of new therapeutic strategies and tools to combat this formidable pathogen
Emerging Issues and Initial Insights into Bacterial Biofilms: From Orthopedic Infection to Metabolomics
No full textBacterial biofilms, enigmatic communities of microorganisms enclosed in an extracellular matrix, still represent an open challenge in many clinical contexts, including orthopedics, where biofilm-associated bone and joint infections remain the main cause of implant failure. This study explores the scenario of biofilm infections, with a focus on those related to orthopedic implants, highlighting recently emerged substantial aspects of the pathogenesis and their potential repercussions on the clinic, as well as the progress and gaps that still exist in the diagnostics and management of these infections. The classic mechanisms through which biofilms form and the more recently proposed new ones are depicted. The ways in which bacteria hide, become impenetrable to antibiotics, and evade the immune defenses, creating reservoirs of bacteria difficult to detect and reach, are delineated, such as bacterial dormancy within biofilms, entry into host cells, and penetration into bone canaliculi. New findings on biofilm formation with host components are presented. The article also delves into the emerging and critical concept of immunometabolism, a key function of immune cells that biofilm interferes with. The growing potential of biofilm metabolomics in the diagnosis and therapy of biofilm infections is highlighted, referring to the latest research
Antibacterial efficacy of conventional and single-use Ni-Ti endodontic instruments: an in vitro microbiological evaluation
No full textPurpose: The purpose of this in vitro study was to investigate the capability of different Ni-Ti instru- ments in disinfecting root canals previously infected with E. faecalis. Methods: 60 single-rooted, freshly extracted teeth were selected, sterilized and inoculated with cells of E. faecalis strain. All root canals were shaped with different Ni-Ti instruments (MTwo, Revo-S, Reciproc, and OneShape) under irrigation with NaOCl and 17% EDTA solutions by the same trained operator. The number of Colony Forming Units (CFU)/ml of E. faecalis was evaluated for each group. Numeric data were submitted to statistical analysis. Results: MTwo, REVO-S, Reciproc and OneShape reported significantly lower CFU/ml values and showed no significant differences among them (p>0.05). All groups showed significantly higher CFU/ ml values than not treated samples (negative control). Conclusions: All the Ni-Ti instrumentation efficiently reduced E. faecalis counts and no significant differences were found among them. Single-use files can offer antibacterial results comparable with traditional instruments
A multiple 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.
Full text linkIn 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
Ozone gel in chronic periodontal disease: A randomized clinical trial on the anti-inflammatory effects of ozone application
Full text linkThe search for new topical treatments able to display not only antimicrobial properties but also a multiplicity of other beneficial effects while expressing safe cytocompatibility toward host tissues is being progressively developed. Antiseptics represent an aid to the gold standard nonsurgical treatment Scaling-and-Root-Planing (SRP) for periodontal disease. This split-mouth study aims to assess the efficacy of the ozonized gel GeliO3 (Bioemmei Srl, Vicenza, Italy) plus SRP (experimental treatment), with respect to SRP + chlorhexidine gel. Ten participants were treated with SRP + chlorhexidine gel (control sites) and with SRP + ozone gel (trial sites). After 1 (T1) and 3 months (T2) from baseline (T0), patients were revisited. At each time-point, the following indexes were assessed: Probing pocket depth (PPD), clinical attachment level (CAL), gingival index (GI), plaque index (PI), and bleeding on probing (BoP). It has been assessed that the use of the ozonized gel in addition to SRP did not show significant differences if compared to conventional SRP + chlorhexidine. Chlorhexidine was found to be more effective than ozone in reducing CAL and GI at T2. Ozone deserves consideration for its wide applicability in several clinical fields. In this connection, we also glance at the latest research on ozone therapy
Vegetable extracts and nutrients useful in the recovery from helicobacter pylori infection: A systematic review on clinical trials
Full text linkHelicobacter pylori (H. pylori) infections affect almost half of the world’s population, with gradually increasing incidence in developed countries. Eradication of H. pylori may provide signifi-cant benefits to the affected individual by healing a number of gastrointestinal and extra-digestive disorders. But due to increased microbial resistance and lack of patient adherence to the therapy, the eradication rate of H. pylori is below 80% with current pharmacological therapies. The usage of botanicals for their therapeutic purposes and medicinal properties have been increased in last decades. They can be use as alternative H. pylori treatments, especially against drug-resistant strains. Epidemiological studies have revealed that people with lower vegetable and micronutrient intake may be at increased risk of H. pylori infection. We have undertaken a review of clinical trials to evaluate the efficacy of vegetable extracts and micronutrients in patients with H. pylori. Various databases, such as Google Scholar, PubMed, Scopus, Web of Science, and the Cochrane Library, were searched for the articles published in English. A total of 24 clinical studies (15 for vegetable extracts and 9 for micronutrients) were selected to be reviewed and summarized in this article. Vegetable extracts (Broccoli sprouts, curcumin, Burdock complex, and Nigella sativa) and micronutrients (vitamin C and E) were not found to be as effective as single agents in H. pylori eradication, rather their efficacy synergized with conventional pharmacological therapies. Conversely, GutGard was found to be significantly effective as a single agent when compared to placebo control
Slime production and expression of the slime-associated antigen (SAA) by staphylococcal clinical isolates
No full textNew resin-based bulk-fill composites: In vitro evaluation of micro-hardness and depth of cure as infection risk indexes
Full text linkThe current in vitro study evaluated the Vickers hardness number (VHN) and hardness ratio of four bulk-fill composites (VisCalor bulk; Admira Fusion x-tra; x-tra fil; and GrandioSO x-tra-Voco, Cuxhaven, Germany) to assess the risk of bacterial colonization in comparison with standard composite materials. Thirty samples were prepared for each group. The VHN of both the external (top) and internal surface (bottom) was determined with a micro-hardness tester (200 g load for 15 s), and the hardness ratio was also calculated for each sample. Subsequently, storage in an acidic soft drink (Coca-Cola, Coca-Cola Company, Milano, Italy) was performed; for each group, 10 samples were stored for 1 day, while another 10 were stored for 7 days and the remaining 10 were kept in water as controls. A significant reduction in VHN was shown for all the groups when comparing the external versus internal side (P < 0.05), although the hardness ratio was greater than 0.80, resulting in an adequate polymerization. Regarding the acid storage, all the groups showed a significant decrease of VHN when compared with the controls, both after 1 day (P < 0.05) and after 7 days (P < 0.001). All the products showed adequate depth of cure without further risk of bacterial colonization. However, acid exposure negatively affected micro-hardness values, which might promote subsequent colonization
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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