Anna Maria Cuffini

Comparative Evaluation of the Antimicrobial Efficacy of a 5% Sodium Hypochlorite Subsonic-activated Solution

INTRODUCTION The study evaluated the efficacy of subsonic agitation of sodium hypochlorite (NaOCl) in reducing bacterial load in the root canal. METHODS Root canals of 112 extracted human single-root teeth were preflared using K-Flexofiles (Dentsply Maillefer, Ballaigues, Switzerland) up to #20 and then shaped using ProTaper S1-S2-F1-F2-F3 (Dentsply Maillefer) at the working length. Irrigation was performed with 33 mL of 5% NaOCl, alternating with 10 mL of 10% EDTA. After ethylene oxide sterilization, the root canals were infected with 30 microL of Enterococcus faecalis culture and randomly assigned to four groups (n = 25) of different irrigation regimens plus positive and negative controls. Irrigation was performed with 2 mL of 5% NaOCl. In the NaOCl 15 group, the irrigant was left in place for 15 seconds, and in the NaOCl 30 group it was left in place for 30 seconds. In the EndoActivator (EA; Dentsply Tulsa Dental Specialties, Tulsa, OK) 15 and EA 30 groups, NaOCl was subsonically agitated with EA for 15 and 30 seconds, respectively. The residual bacterial count was then evaluated. Differences among groups were analyzed with one-way analysis of variance and the post hoc Bonferroni test (p < 0.05). RESULTS A statistically significant difference was evidenced among groups (F(3) = 9.01, p < 0.001). The standard irrigation groups (NaOCl 15 and 30) showed higher microbial counts than the EA 30 group (p < 0.05). CONCLUSION Thirty seconds of NaOCl subsonic agitation with EndoActivator appears to be slightly more effective in reducing bacterial load in the root canal compared with NaOCl irrigation alone.

Vitamin E blended Uhmwpe may have the potential to reduce bacterial adhesive ability

Biomaterial‐associated infection (BAI), a clinical problem resulting in septic failure of joint replacement implants, is initiated by bacterial adhesion, often by Staphylococcus epidermidis. Ultra high molecular weight polyethylene (UHMWPE) is a material of choice for joint replacement; reducing the adhesion of S. epidermidis to the polymer could be a means to decrease infection. We examined the adhesion of two ATCC and one clinical strain of S. epidermidis to standard polyethylene (PE), vitamin E blended UHMWPE (VE‐PE), and oxidized UHMWPE (OX‐PE) after different incubation times: a significant (p < 0.01) decrease in the adhered staphylococci on VE‐PE and a significantly higher incidence of the dislodged biofilm bacteria on OX‐PE was observed compared with that registered on PE. With attenuated total reflectance (ATR)–FTIR spectroscopy before and after suspension in bacterial medium for 48 h, new absorptions were observed mainly in OX‐PE, indicating adsorption of protein‐like substances on the polymer surface. We hypothesized that the different hydrophilicity of the surfaces with different chemical characteristics influenced protein adsorption and bacterial adhesion. These results may have clinical implications concerning the prevention of septic loosening: the VE‐PE could have the potential to reduce S. epidermidis adhesive ability if the preliminary data observed in these selected strains is further confirmed, as diversity among clinical strains is well known. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1662–1667, 2011

Solid lipid nanoparticles as promising tool for intraocular tobramycin delivery: Pharmacokinetic studies on rabbits

Eye drops are widely accepted as formulations for targeting the anterior segment notwithstanding their limitations in terms of bioavailability. The unique structure of the eye requires specially-designed formulations able to favor the pharmacokinetic profile of administered drugs, mainly minimizing the influence of ocular barriers. Nanotechnology-based delivery systems lead to significant technological and therapeutical advantages in ophthalmic therapy. The aim of the present study was to determine whether tobramycin as ion-pair incorporated in mucoadhesive Solid Lipid Nanoparticles (SLN) reaches the inner parts of the eye favoring drug activity. After technological characterization of the tobramycin entrapped SLN formulation (Tobra-SLN), a pharmacokinetic study in rabbits after topical instillation and intravenous administration of the formulation has been carried out. In addition, the intracellular activity of Tobra-SLN formulation against phagocytosed Pseudomonas aeruginosa was investigated. The SLN were spherical in shape, and showed a hydrodynamic diameter of about 80nm, a negative zeta potential (-25.7mV) with a polydispersity index of 0.15, representative of a colloidal dispersion with high quality, characterized by an unimodal relatively narrow size distribution. As demonstrated by FTIR and DSC, tobramycin ion-pair could be concentrated into lipid inner core of SLN, without interaction with the stearic acid, thus promoting a slow and constant drug release profile in the dissolution medium. Surprisingly, the drug concentration was significantly higher in all ocular tissues after ocular and intravenous administration of Tobra-SLN formulation with respect to reference formulations and only Tobra-SLN allowed the penetration of drug into retina. Furthermore, the use of Tobra-SLN resulted in both higher intraphagocytic antibiotic concentrations in polymorphonuclear granulocytes and greater bactericidal activity against intracellular Pseudomonas aeruginosa, probably due to the ability of Tobra-SLN to penetrate either into phagocytic cells, or alternatively to cross bacterial barrier. The present study broadens the knowledge on the use of SLN as carriers for ocular drug delivery to the posterior chamber and might open new avenues for treatment of ocular infections, representing a strategy to overcome the microbial resistance.

Non-dermatophyte moulds as skin and nail foot mycosis agents: Phoma herbarum, Chaetomium globosum and Microascus cinereus

The increased prevalence of dermatomycoses along with the wide range of organisms now recognized as potential pathogens needs accurate laboratory isolation and identification of the aetiological agents. In this report three cases of foot dermatomycoses due to filamentous fungi commonly present in the environment with ubiquitous distribution are described in immunocompetent subjects. Skin and nail samples were collected, suspended in 20% KOH solution, examined under a light microscope and cultured in Mycobiotic agar and Sabouraud dextrose agar containing chloramphenicol to detect fungal growth. Phoma herbarum, Chaetomium globosum, and Microascus cinereus were isolated and identified.

In Vitro Activities of Fluconazole and Voriconazole against Clinical Isolates of Candida spp. Determined by Disk Diffusion Testing in Turin, Italy

ABSTRACT The in vitro activities of fluconazole and voriconazole against 1,024 clinical isolates of Candida spp. were determined by the agar disk diffusion test using the Clinical and Laboratory Standards Institute (CLSI) M44-A guidelines. The results of this investigation demonstrated the broad-spectrum in vitro activity of voriconazole, relative to that of fluconazole, against yeasts tested, in particular fluconazole-resistant isolates, such as Candida krusei that showed high susceptibility to voriconazole. The situation in Turin, Italy, is quite similar to that of the rest of Italy, reflecting the worldwide trend.

Schizophyllum commune: an unusual of agent bronchopneumonia in an immunocompromised patient

We report a case of bronchopneumonia due to Schizophyllum commune in an immunocompromised patient. While this fungus rarely causes disease in humans, it has been reported in association with several clinical entities and lung disorders. A 59-year-old white man with a gastric carcinoma was admitted to S. Giovanni Battista Hospital (Turin, Italy). Three days after the admission, he developed a bronchopneumonia, which was diagnosed through the use of X-ray and showed an abnormal infiltrative shadow. Samples of bronchial aspirate were collected for laboratory microbiological investigation. Direct microscopic examination of these specimens revealed the presence of numerous septate, hyaline hyphae and rare clamp connections. Sabouraud Dextrose Agar and Columbia agar plus 5% blood media inoculated with portions of the same specimens yielded, after 4-5 days of incubation at 25 degrees C and 37 degrees C, a cottony white mould. The fungus was identified on the basis of its macroscopic and microscopic morphology. The macroscopic examination of the colony showed raised, curved, fan-shaped and shell-like basidiocarps. The microscope examination revealed the presence of hyaline, septate hyphae with clamp connections and short, thin spicules. The fungal isolate was identified as S. commune. The patient was cured after therapy with intravenous fluconazole (600 mg twice daily for over six weeks).

Antimicrobial chitosan nanodroplets: new insights for ultrasound-mediated adjuvant treatment of skin infection

BACKGROUND Chronic wounds, characterized by hypoxia, inflammation and impaired tissue remodeling, are often worsened by bacterial/fungal infections. Intriguingly, chitosan-shelled/decafluoropentane-cored oxygen-loaded nanodroplets (OLNs) have proven effective in delivering oxygen to hypoxic tissues. AIM The present work aimed at investigating nanodroplet antimicrobial properties against methicillin-resistant Staphylococcus aureus (MRSA) or Candida albicans, toxicity on human keratinocytes (HaCaT) and ultrasound (US)-triggered transdermal delivery. MATERIALS & METHODS Nanodroplet antibacterial/antifungal properties, human cytotoxicity, and US-triggered transdermal delivery were measured through microbiological, biochemical, and sonophoresis assays, respectively. RESULTS OLNs and oxygen-free nanodroplets (OFNs) displayed short- or long-term cytostatic activity against MRSA or Candida albicans, respectively. OLNs were not toxic to keratinocytes, whereas OFNs slightly affected cell viability. Complementary US treatment promoted OLN transdermal delivery. CONCLUSION As such, US-activated chitosan-shelled OLNs appear as promising, nonconventional and innovative tools for adjuvant treatment of infected chronic wounds.

Synergistic effect of erythromycin on polymorphonuclear cell antibacterial activity against erythromycin-resistant phenotypes of Streptococcus pyogenes

To evaluate the synergistic activity of erythromycin and human polymorphonuclear cells (PMNs) on the binomial erythromycin-resistant (ERY(R)) Streptococcus pyogenes/host, the phagocytic and bactericidal activities of PMNs against ERY(R) streptococcal strains (cMLS(B), M, and iMLS(B) A, B and C phenotypes) were assessed in the presence of the macrolide. The results showed that when erythromycin, PMNs and streptococci [both erythromycin-sensitive (ERY(S)) and ERY(R)] were simultaneously present in the culture medium, PMN phagocytic activity was similar to that of drug-free controls. In contrast, the results emphasised a significant high increase in intracellular killing by PMNs in the presence of erythromycin not only for ERY(S) streptococci but also for ERY(R)S. pyogenes with high (cMLS(B), iMLS(B) A and iMLS(B) B phenotypes) and moderate (M and iMLS(B) C phenotypes) erythromycin resistance compared with controls without drug. From literature data it emerged that, even if intracellularly concentrated, erythromycin is relatively inactive because of its instability. The results indicate that the enhanced intra-PMN streptococcal killing detected is mainly attributable to PMN bactericidal systems that synergise with intracellular erythromycin in eradicating ERY(R)S. pyogenes strains (both with high and moderate resistance). These data confirm that the antibiotic resistance detected in vitro does not always imply a failure of antimicrobial treatment.

Incidence and risk factors for acute infection after proximal humeral fractures: a multicenter study

BACKGROUND The rate of acute infection after surgery for proximal humeral fractures is not known. The aims of this study were to report the incidence and to analyze the risk factors for infection after proximal humeral fracture treatment. MATERIALS AND METHODS We report a retrospective multicenter study of 452 proximal humeral fractures. Data were modeled by use of univariate and/or linear regression analyses to determine the odds ratio (OR). A logistic regression analysis was used to check for demographic and other characteristics with the potential to confound a true association between risk factors and infection. RESULTS The mean age was 62.1 years, and 314 patients were female patients. Of the patients, 18 (4%) had an acute infection. The factors that correlated with infection were length of surgery (OR, 1.009; P = .05), preoperative skin preparation with chlorhexidine gluconate (OR, 0.13; P = .008), and prophylactic antibiotic (OR, 10.73; P = .03). The delay to surgery was close to achieving significance (OR, 1.71; P = .06). CONCLUSION This study suggests that washing the shoulder with chlorhexidine gluconate and avoiding the use of first-generation cephalosporin in favor of more effective prophylactic therapy are effective at reducing the risk of infection after treatment for proximal humeral fractures.

Synergy of Caspofungin with Human Polymorphonuclear Granulocytes for Killing Candida albicans

ABSTRACT The influence of caspofungin on polymorphonuclear leukocyte (PMN) phagocytosis and intracellular killing of Candida albicans was investigated. Caspofungin, at all of the concentrations tested (2, 3.2, and 8 μg/ml), significantly increased intracellular killing by PMNs through its direct action on both yeast cells and PMNs, indicating the potential ability of caspofungin to synergize with phagocytes for candidal killing. Caspofungin may therefore constitute an effective therapeutic option for the treatment of invasive fungal infections, including those refractory to conventional treatment with azole agents.