Inhibition of Candida albicans adhesion on medical-grade silicone by a Lactobacillus-derived biosurfactant.

AIMS: The study aimed at investigating the ability of biosurfactant (BS) produced by a Lactobacillus brevis isolate (CV8LAC) to inhibit adhesion and biofilm formation of Candida albicans on medical-grade silicone elastomeric disks (SEDs). METHODS AND RESULTS: Biosurfactant activity was evaluated at physiological conditions, by means of co-incubation and precoating assays. Additionally, BS extract was tested for antifungal susceptibility against C. albicans in both planktonic and sessile form. Biofilm covered surface and hyphae and blastospores occurrence were quantified by scanning electron microscopy (SEM) and image analysis. BS did not inhibit growth of C. albicans in both planktonic and sessile form. Nevertheless, co-incubation with 2000 µg ml(-1) BS significantly reduced biofilm formation on SEDs surface by 89, 90 and 90% after 24, 48 and 72 h of incubation. Fungal adhesion and biofilm formation to precoated SEDs was reduced by 62, 53, 50 and 44% after 1.5, 24, 48 and 72 h. SEM showed a significant reduction of biofilm covered surface in precoated disks but no differences in the production of hyphae or blastospores, except at 1.5 h of incubation. CONCLUSIONS: This study demonstrated that CV8LAC BS has the ability to counteract significantly the initial deposition of C. albicans to silicone surfaces and to effectively slow biofilm growth. SIGNIFICANCE AND IMPACT OF THE STUDY: The anti-adhesive properties of the CV8LAC BS suggest a potential role of the coating for preventing fungal infection associated to silicone medical devices.

Different experimental protocols for decontamination affect the cleaning of medical devices. A preliminary electron microscopy analysis.

The aim of the present study was to examine the efficiency of different decontamination-cleaning protocols on blood-soiled catheters used for interventional cardiology. Electrophysiology and cardiac ablation disposable devices were contaminated with bacteria-spiked human blood and underwent four different pre-sterilization protocols, including a chlorine-releasing agent, a polyphenolic emulsion, and an enzymatic detergent. Treated samples were examined by optical microscopy, scanning electron microscopy and transmission electron microscopy to identify and characterize biological and inorganic residuals. The use of chlorine as a first treatment caused denaturation of serum proteins and adherence of blood components to the surface of the device, thus hindering the cleaning efficiency of subsequent treatments with enzymatic detergents. An enzymatic/chlorine protocol was more efficient, but was considered to be a greater risk to healthcare staff. Polyphenolic-based treatments had the highest level of efficiency in bioburden removal, but interaction and adsorption of this class of chemicals onto biopolymers might lead to serious concerns about toxicity on subsequent reuse. Adequate pre-sterilization cleaning is fundamental for sterilization success and high-resolution electron microscopy can provide significant and detailed information about the efficiency of chemicals used for cleaning a blood-soiled device.

Multidisciplinary approach for in-deep assessment of joint prosthesis failure.

In spite of advancement in biomaterials and biomechanics, in development of new osteo-integrative materials and coatings, and in macro- micro- component design, a non negligible fraction of the implanted prosthesis fails before the expected lifetime. A prospective observational clinical study has been conducted to define and apply a set of experimental techniques to in-deep assess the failure of joint prosthesis. Microbiological, histological and micro-structural techniques were implemented to specifically address phenomena occurring at the tissue-implant interface. Results obtained from 27 cases of prosthetic joint failure are discussed in terms of sensitivity and specificity. A procedural flow-chart is finally proposed for the assessment of joint prosthesis failure.

Health technology assessment on reprocessing single-use catheters for cardiac electrophysiology: results of a three-years study.

The study aims to define the technical, ethical, juridical and economic issues involved in the assessment of a reprocessing policy for single-use interventional cardiac devices (SUDs). The feasibility of reprocessing was evaluated for cardiac electrophysiology catheters by comparing the chemical, physical and functional properties of new and reprocessed devices. The issue of hygiene was addressed by developing microbiological tests for the quantification of bioburden, sterility and pyrogenic load. The results of more than 1500 tests, conducted on 531 catheters, suggested a precautionary number of regenerations of five cycles. The ethical aspects were reviewed and the European juridical framework was assessed, revealing a need for harmonization. Applying a specific economic model, potential savings were calculated for a representative cardiology department and estimated at national and European level. Potential savings of 41.2% and 32.9% were calculated for diagnostic and ablation catheters, respectively. Safe and effective reprocessing of SUDs could be pursued if quality control processes and certified procedures are met. A reprocessing policy in EP laboratory could lead to savings of about 27,250 euros per 100,000 population, but the economic benefits are strongly dependent on the maximum number of regenerations and the regeneration rate.