Valeria Allizond

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

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.

Interplay between surface properties of standard, vitamin E blended and oxidised ultra high molecular weight polyethylene used in total joint replacement and adhesion of Staphylococcus aureus and Escherichia coli

We have assessed the different adhesive properties of some of the most common bacteria associated with periprosthetic joint infection on various types of ultra high molecular Weight Polyethylene (UHMWPE). Quantitative in vitro analysis of the adhesion of biofilm producing strains of Staphylococcus aureus and Escherichia coli to physically and chemically characterised standard UHMWPE (PE), vitamin E blended UHMWPE (VE-PE) and oxidised UHMWPE (OX-PE) was performed using a sonication protocol. A significant decreased bacterial adhesion was registered for both strains on VE-PE, in comparison with that observed on PE, within 48 hours of observation (S. aureus p = 0.024 and E. coli p = 0.008). Since Vitamin E reduces bacterial adhesive ability, VE-stabilised UHMWPE could be valuable in joint replacement by presenting excellent mechanical properties, while reducing bacterial adhesiveness.

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.

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.

Role of caspofungin in restoring the impaired phagocyte-dependent innate immunity towards Candida albicans in chronic haemodialysis patients

Phagocyte-dependent cellular immunity in chronic kidney disease patients undergoing haemodialysis treatment is frequently impaired owing to the uraemic state, resulting in an intrinsic susceptibility to developing invasive fungal infections with high mortality rates. Since synergism between phagocytic cells and antifungal drugs may be crucial for successful therapy, the aim of this study was to evaluate the effects exerted by caspofungin (CAS) on the functional activities of polymorphonuclear cells (PMNs) in haemodialysed patients (HDs) towards Candida albicans compared with those of PMNs from healthy subjects (HSs). PMNs were separated from venous blood samples of 66 HDs and 30 HSs (as controls), and measurement of phagocytic and intracellular fungicidal activities of HD-PMNs and HS-PMNs was performed in the presence of CAS at the minimum inhibitory concentration (MIC) and at sub-MICs. CAS-free controls were also included. In the drug-free test condition, no significant difference between the phagocytic activity of HD-PMNs and HS-PMNs was detected. In contrast, a progressive decline in the intracellular killing activity of HD-PMNs against proliferating yeasts was observed. CAS at MIC and sub-MIC levels was able to improve significantly the intracellular fungicidal activity of HD-PMNs against C. albicans, restoring their functionality. These findings provide evidence that CAS exerts a synergistic effect on HD-PMNs against C. albicans, being able to strength the depressed intracellular killing activity. These results corroborate the use of CAS as an effective therapeutic option for the treatment of invasive fungal infections in HDs, in whom even a marginal influence of antifungal drugs on host response may have a relevant effect.

In vitro compared activity of telithromycin and azithromycin against northwest Italian isolates of Streptococcus pyogenes and Streptococcus pneumoniae with different erythromycin susceptibility.

Aims:  This study compared the in vitro activity of telithromycin with that of azithromycin against 438 Streptococcus pyogenes and 198 Streptococcus pneumoniae, isolated over the period 2005–2007 from specimens of different human origin obtained in three Piemonte Region’s hospitals.