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Introduction The use of antibiotic-loaded polymethylmethacrylate bone-cement spacers during two-stage exchange procedures is the standard in the treatment of patients with delayed prosthetic joint infection. The real antimicrobial activity of these spacers is unclear because the adherence of bacteria to cement might result in clinical recurrence of infection. The purpose of the study is to evaluate the in vitro formation of Pseudomonas Aeruginosa (PA) and Staphylococcus spp. biofilm on antibiotic-loaded bone cement. Materials and methods Cement disks (diameter = 6 mm) impregnated with gentamicin and colistin were submerged in bacterial suspensions of Methicillin-resistant Staphylococcus Aureus(MRSA), Staphylococcus epidermidis (SE), and PA. Negative controls (specimen disks without antibiotic) were similarly prepared. Biofilm formation was visualized by confocal scanning laser microscopy (CSLM), after staining the discs with the live/dead BacLight viability stain containing SYTO 9 dye and propidium iodide. Images from five randomly selected areas were acquired for each disc. Sequential optical sections of 2 µm were collected in sequence along the z-axis over the complete thickness of the sample. The resulting stacks of images were analyzed, quantified and rendered into three-dimensional (3D). The biofilm thickness on antibiotic bone cement compared with the controls was automatically evaluated. Results CSLM showed living bacteria and bacterial biofilm on the surface of all cement disks, either antibiotic-loaded or controls. Mean biofilm thickness on the controls was 29.6 µm for MRSA, 32.3 µm for SE, and 59.7 µm for PA. The 3D rendering showed decrease in the biofilm thickness for all bacterial strains on gentamicin- and colistin-impragnated cement disks as compared with the controls. The incorporation of gentamicin into cement resulted in a 54%, 74%, and 45% reduction in the bacterial biofilm thickness for MRSA, PA and SE, respectively. The use of colistin leaded to a 51 % reduction in the PA biofilm thickness. Conclusion The bacterial viability and biofilm formation are reduced by adding antibiotics to bone cement but antibiotic-loaded bone cement does not completely inhibit the formation of an infectious biofilm in vitro.

Nowadays, silver nanoparticles are in the limelight to control infection during wound healing process and a vast variety of antimicrobial dressings based on colloidal silver have been marketed to fight wound invasion of pathogen bacteria, which represents one of the main adverse effects limiting the repair process. Here we propose a biofunctional hydrogel based on alginate (ALG) and hyaluronic acid (HA) embedding ultrasmall silver nanoparticles (usSN, 3 and glucono-δ-lactone. To follow usSN release from the hydrogels in aqueous media, catalytic activity of usSN-loaded hydrogels was evaluated. Results suggested that catalytic activity was low in intact hydrogels and high when hydrogels dissolved, which suggests that usSN firmly interact with polymer chains and are availabile in the medium depending on the extent of hydrogel degradation. HA-containing hydrogels showed faster dissolution in simulated physiological conditions and higher antibiofouling properties as compared to hydrogels made only of ALG. Free usSN were not toxic toward human Mesenchymal Stem Cells (Ad-MSCs), previously isolated from subcutaneous adipose tissue biopsies, up to 50 µg/mL. At this concentration, viability of Ad-MSCs was unaffected whereas their motility was significantly higher as compared to control (P in vivo investigation.

Antibiotic therapy has resulted in major progress in the fight against infectious diseases and is associated with an improved quality of life and increased survival. However, the emergence of resistant bacterial strains represents an inevitable consequence of antibiotic treatment and yields a loss of beneficial effects. Due to the scarce availability of new molecules in the near future, physicians have to learn how to best use currently available molecules. The aim of the present study was to evaluate the criteria that physicians use in choosing targeted antibiotic therapy. To achieve this goal, we used a questionnaire comprising seven questions. The questionnaire was administered, with the guarantee of anonymity, to a pool of physicians at the Federico II University Hospital of Naples who could prescribe antibiotics. Of the physicians interviewed, 68% chose antibiotic therapy autonomously or in cooperation with other doctors of the same structure, whereas 30% of interviewees referred to the infectious diseases consultant (8% after the first bacterial isolation and 22% after antibiotic therapy failure). The definition and meaning of minimum inhibitory concentration (MIC) were known to the vast majority of physicians (82% and 83%, respectively). In contrast, few of the interviewees knew the definition or meaning of breakpoint (16% and 17%, respectively). The key question of the questionnaire focused on the main criterion for antibiotic choice: 68% of interviewees gave an incorrect answer, most interviewees considering only the lowest MIC value for the isolated bacterium as the fundamental parameter in antibiotic choice. Our study shows that antibiotic therapy in a teaching hospital is often chosen using inappropriate criteria. Due to the well-known effects of the wrong antibiotic choice on therapeutic failure rate and on healthcare cost, information and training programmes for physicians who prescribe antibiotics are urgently needed.

Bartonella henselae, the etiologic agent of cat-scratch disease, causes a self-limited syndrome of fever and regional lymphadenopathy in immunocompetent hosts. In immunocompromised hosts, however, B. henselae can cause severe disseminated disease and pathologic vasoproliferation known as bacillary angiomatosis or bacillary peliosis. The role of the host immune response to B. henselae is critical in preventing progression tosystemic disease. The spectrum of disease, diagnosis and management of B. henselae infection in solid organ transplant recipients has not been well characterized. Only rare cases of bartonellosis in transplant recipients have been reported. The purpose of this study has been to determine the seroprevalence of B. henselae in patients awaiting heart transplantation, in our Regional Reference Transplantation Centre. The diagnosis of B. henselae is usually based on serological methods immunoglobulin M (IgM), IgG] because they are practical, simple and rapid. Serum samples from 21 (16 males and 5 females) patients awaiting heart transplantation, with a median age of 53±15 SD (range 8???68 years), were examined by indirect immunofluorescence assay. In our study we have found a B. henselae antibody positivity rate of 19.04% (4/21) and in particular, 1 of 21 (4.76%) patients presented IgM while 3 of 21 (14.28%) presented IgG. Our preliminary serological data seems to indicate that B. henselae is present in our area and more interestingly it can be also present in patients awaiting heart transplantation. Thus, on the basis of our data, we would recommend the importance of including B. henselae diagnosis also in pre-transplant patients.

Aim: Bartonella henselae, the etiologic agent of cat-scratch disease, causes a self-limited syndrome of fever and regional lymphadenopathy in immunocompetent hosts. In immunocompromised hosts, however, B. henselae can cause severe disseminated disease and pathologic vasoproliferation known as bacillary angiomatosis or bacillary peliosis. The spectrum of disease, diagnosis and management of B. henselae infection in solid organ transplant recipients has not been well characterized. The purpose of this study has been to determine the seroprevalence of B. henselae in patients awaiting heart transplantation, in our Regional Reference Transplantation Centre. Methods: The diagnosis of B. henselae is usually based on serological methods (IgM, IgG). Immunofluorescent assays (IFA) are used for the detection of IgG or IgM antibodies against specific antigens. Bartonella IgM and IgG test kits are designed to detect the antigen-antibody complexes when diluted sera are presented with Bartonella antigens on commercially produced slides. A fluorescein-labeled anti-IgG or IgM conjugate is responsible for visualization of reactions. Results: Serum samples from 21 (16M, 5F) patients awaiting heart transplantation, with a median age of 53 ± 15SD (range 8-68 years) and 20 healthy donors (10M and 10F), with a median age of 37 ± 5.9SD (range 28-49 years) were examined by indirect immunofluorescence assay. In our study we have found, in patients awaiting heart transplantation, a B. henselae antibody positivity rate of 19.04% (4/21) and in particular, 1/21 (4.76%) patients presented IgM while 3/21 (14.28%) presented IgG. All healthy donors were found negative. Conclusions: Our preliminary serological data seems to indicate that B. henselae is present in our area and more interestingly it can be also present in patients awaiting heart transplantation. Thus, on the basis of our data, we would recommend the importance of including B. henselae diagnosis also in pre-transplant patients.