Bacterial colonization status of cystic fibrosis children's toothbrushes: A pilot study

BACKGROUND

Pseudomonas aeruginosa and Staphylococcus aureus toothbrush contamination in cystic fibrosis (CF) is unknown. This pilot study aimed to determine their prevalence and the potential involvement of toothbrushes in pulmonary infection.

METHODS

Toothbrush bacteriological analysis for children aged 8-18 years was conducted on 27 CF patients, 15 healthy siblings, and 15 healthy children from the general population.

RESULTS

S. aureus was detected on 22% of the patients' toothbrushes, and 13% of healthy children's toothbrushes and P. aeruginosa on 15% of patients' toothbrushes and 0-13% of healthy children's toothbrushes. There was no statistical correlation between pulmonary colonization and toothbrush contamination. P. aeruginosa genotyping showed two identical clones on the patients' toothbrushes and in their sputum, and between one patient's sputum and his sibling's toothbrush.

CONCLUSION

S. aureus and P. aeruginosa can colonize CF patients' toothbrushes. The impact on pulmonary colonization remains unknown. Toothbrush decontamination methods need to consider these bacteria in CF patients.

Consensus statement: patient safety, healthcare-associated infections and hospital environmental surfaces

Healthcare-associated infections have serious implications for both patients and hospitals. Environmental surface contamination is the key to transmission of nosocomial pathogens. Routine manual cleaning and disinfection eliminates visible soil and reduces environmental bioburden and risk of transmission, but may not address some surface contamination. Automated area decontamination technologies achieve more consistent and pervasive disinfection than manual methods, but it is challenging to demonstrate their efficacy within a randomized trial of the multiple interventions required to reduce healthcare-associated infection rates. Until data from multicenter observational studies are available, automated area decontamination technologies should be an adjunct to manual cleaning and disinfection within a total, multi-layered system and risk-based approach designed to control environmental pathogens and promote patient safety.

Dynamic Mechanisms of the Bactericidal Action of an Al2O3-TiO2-Ag Granular Material on an Escherichia coli Strain

The bactericidal activity of an Al2O3-TiO2-Ag granular material against an Escherichia coli strain was confirmed by a culture-based method. In particular, 100% of microorganisms were permanently inactivated in 30 to 45 min. The present work aimed to investigate the mechanisms of the bactericidal action of this material and their dynamics on Escherichia coli using different techniques. Observations by transmission electron microscopy (TEM) at different times of disinfection revealed morphological changes in the bacteria as soon as they were put in contact with the material. Notably highlighted were cell membrane damage; cytoplasm detachment; formation of vacuoles, possibly due to DNA condensation, in association with regions exhibiting different levels of electron density; and membrane lysis. PCR and flow cytometry analyses were used to confirm and quantify the observations of cell integrity. The direct exposure of cells to silver, combined with the oxidative stress induced by the reactive oxygen species (ROS) generated, was identified to be responsible for these morphological alterations. From the first 5 min of treatment with the Al2O3-TiO2-Ag material, 98% of E. coli isolates were lysed. From 30 min, cell viability decreased to reach total inactivation, although approximately 1% of permeable E. coli cells and 1% of intact cells (10(5) genomic units·ml(-1)) were evidenced. This study demonstrates that the bactericidal effect of the material results from a synergic action of desorbed and supported silver. Supported silver was shown to generate the ROS evidenced.

Bactericidal activity of 3 cutaneous/mucosal antiseptic solutions in the presence of interfering substances: Improvement of the NF EN 13727 European Standard?

OBJECTIVE

There is no standard protocol for the evaluation of antiseptics used for skin and mucous membranes in the presence of interfering substances. Our objective was to suggest trial conditions adapted from the NF EN 13727 standard, for the evaluation of antiseptics used in gynecology and dermatology.

METHODS

Three antiseptic solutions were tested in vitro: a chlorhexidine-benzalkonium (CB) combination, a hexamidine-chlorhexidine-chlorocresol (HCC) combination, and povidone iodine (P). The adaptation of trial conditions to the standard involved choosing dilutions, solvent, and interfering substances. The activity of solutions was assessed on the recommended strains at concentrations of 97% (pure solution), 50%, and 10% (diluted solution), and 1%. A logarithmic reduction ≥ 5 was expected after 60seconds of contact, to meet requirements of bactericidal activity.

RESULTS

HCC did not present any bactericidal activity except on P. aeruginosa at a concentration of 97%. P was not bactericidal on E. hirae at any concentration and on S. aureus at 97%. CB had the most homogeneous bactericidal activity with a reduction>5 log on the 4 bacterial strains at concentrations of 97%, 50% and 10%.

CONCLUSION

Adapting the NF EN 13727 standard allowed assessing the 3 tested solutions: only CB was bactericidal in dirty conditions. This study proved the possibility of validating antiseptic choice in vitro, in current practice conditions, for adjunctive treatment of skin and mucous membranes disorders, primarily of bacterial origin or with a potential of superinfection.

Protons accumulation during anodic phase turned to advantage for oxygen reduction during cathodic phase in reversible bioelectrodes

Reversible bioelectrodes were designed by alternating acetate and oxygen supply. It was demonstrated that the protons produced and accumulated inside the biofilm during the anodic phase greatly favored the oxygen reduction reaction when the electrode was switched to become the biocathode. Protons accumulation, which hindered the bioanode operation, thus became an advantage for the biocathode. The bioanodes, formed from garden compost leachate under constant polarization at -0.2 V vs. SCE, were able to support long exposure to forced aeration, with only a slight alteration of their anodic efficiency. They produced a current density of 16±1.7 A/m2 for acetate oxidation and up to -0.4 A/m2 for oxygen reduction. Analysis of the microbial communities by 16S rRNA pyrosequencing revealed strong selection of Chloroflexi (49±1%), which was not observed for conventional bioanodes not exposed to oxygen. Chloroflexi were found as the dominant phylum of electroactive biofilms for the first time.

Impact of tortuous flow on bacteria streamer development in microfluidic system during filtration

The way in which bacterial communities colonize flow in porous media is of importance, but basic knowledge on the dynamic of these phenomena is still missing. The aim of this work is to develop microfluidic experiments in order to progress in the understanding of bacteria capture in filters and membranes. PDMS microfluidic devices mimicking filtration processes have been developed to allow a direct dynamic observation of bacteria across 10 or 20 μm width microchannels. When filtered in such devices, bacteria behave surprisingly: Escherichia coli, Pseudomonas aeruginosa or Staphylococcus aureus accumulate in the downstream zone of the filter and form large streamers which oscillate in the flow. In this study, streamer formation is put in evidence for bacteria suspension in non nutritive conditions in less than 1 h. This result is totally different from the one observed in same system with "inert" particles or dead bacteria which are captured in the bottleneck zone and are accumulated in the upstream zone. Observations within different flow geometries (straight channels, connected channels, and staggered row pillars) show that the bacteria streamer development is influenced by the flow configuration and, particularly by the presence of tortuosity within the microchannels zone. These results are discussed at the light of 3D flow simulations. In confined systems and in laminar flow, there is secondary flow (z-velocities) superimposed to the streamwise motion (in xy plane). The presence of the secondary flow in the microsystems has an effect on the bacterial adhesion. A scenario in three steps is established to describe the formation of the streamers and to explain the positive effect of tortuous flow on the development kinetics.

Composition and properties of silver-containing calcium carbonate-calcium phosphate bone cement

The introduction of silver, either in the liquid phase (as silver nitrate solution: Ag(L)) or in the solid phase (as silver phosphate salt: Ag(S)) of calcium carbonate-calcium phosphate (CaCO3-CaP) bone cement, its influence on the composition of the set cement (C-Ag(L) and C-Ag(S) cements with a Ca/Ag atomic ratio equal to 10.3) and its biological properties were investigated. The fine characterisation of the chemical setting of silver-doped and reference cements was performed using FTIR spectroscopy. We showed that the formation of apatite was enhanced from the first hours of maturation of C-Ag(L) cement in comparison with the reference cement, whereas a longer period of maturation (about 10 h) was required to observe this increase for C-Ag(S) cement, although in both cases, silver was present in the set cements mainly as silver phosphate. The role of silver nitrate on the setting chemical reaction is discussed and a chemical scheme is proposed. Antibacterial activity tests (S. aureus and S. epidermidis) and in vitro cytotoxicity tests (human bone marrow stromal cells (HBMSC)) showed that silver-loaded CaCO3-CaP cements had antibacterial properties (anti-adhesion and anti-biofilm formation) without a toxic effect on HBMSC cells, making C-Ag(S) cement a promising candidate for the prevention of bone implant-associated infections.

Calculation of intraocular lens surface free energy and its components from contact angle measurements

One of the most important biomaterial characteristics involved in bacterial adhesion on intraocular lenses (IOLs) is hydrophobicity. We calculated the hydrophobicity parameters of IOLs made of 6 different materials (polymethylmethacrylate, PMMA, heparin surface-modified PMMA, HSM-PMMA, silicone, hydrophilic and hydrophobic acrylics and collamer). Values of IOL surface free energy components were determined from contact angle measurements, using the Fowkes, Owens-Wendt and Good-van Oss calculations. Contact angles were higher for silicone and hydrophobic acrylic materials and lower for collamer and hydrophilic acrylic materials. The values of IOL surface free energy components obtained with the 3 different calculations were homogenous. According to the Owens-Wendt calculation, the IOLs could be separated into dispersive implants (hydrophobic acrylic, silicone and PMMA) and polar implants (collamer, hydrophilic acrylic and HSM-PMMA).

Bifunctional silica nanoparticles for the exploration of biofilms of Pseudomonas aeruginosa

Luminescent silica nanoparticles are frequently employed for biotechnology applications mainly because of their easy functionalization, photo-stability, and biocompatibility. Bifunctional silica nanoparticles (BSNPs) are described here as new efficient tools for investigating complex biological systems such as biofilms. Photoluminescence is brought about by the incorporation of a silylated ruthenium(II) complex. The surface properties of the silica particles were designed by reaction with amino-organosilanes, quaternary ammonium-organosilanes, carboxylate-organosilanes and hexamethyldisilazane. BSNPs were characterized extensively by DRIFT, (13)C and (29)Si solid state NMR, XPS, and photoluminescence. Zeta potential and contact angle measurements exhibited various surface properties (hydrophilic/hydrophobic balance and electric charge) according to the functional groups. Confocal laser scanning microscopy (CLSM) measurements showed that the spatial distribution of these nanoparticles inside a biofilm of Pseudomonas aeruginosa PAO1 depends more on their hydrophilic/hydrophobic characteristics than on their size. CLSM observations using two nanosized particles (25 and 68 nm) suggest that narrow diffusion paths exist through the extracellular polymeric substances matrix.

Activity of Drill® lozenges on the main microorganisms responsible for upper respiratory tract infections

OBJECTIVES

The treatment of sore throat, considered to be essentially due to viral infection, does not require the use of antibiotics. The recommended treatment is therefore based on the use of topical anaesthetics and antiseptics. Throat lozenges play a leading role in topical treatment by allowing immediate, massive and persistent release of the active molecule at the site of infection. The objective of this study was to demonstrate the short-term and long-term in vitro antimicrobial efficacy of Drill(®) lozenges in relation to the main pathogens responsible for upper respiratory tract infections.

MATERIAL AND METHOD

The bactericidal and virucidal activity in relation to the main microorganisms responsible for upper respiratory tract infections, including the H1N1 influenza virus, was evaluated after short (5 minutes) and long (3h) contact times, according to a methodology complying with European standards for the evaluation of chemical antiseptics and disinfectants. In parallel, the global antibacterial activity was determined on 30 strains representative of the resident flora by determination of maximum inhibitory dilutions (MID) and maximum bactericidal dilutions (MBD).

RESULTS

Drill(®) lozenges presented an antibacterial activity inducing significant (>90%) destruction of the main upper respiratory tract pathogens after a 5-minute contact time at high concentration and after a 3-hour contact time after dilution. Drill(®) lozenges also exerted an antiviral activity inducing 2 log (99%) destruction of the H1N1 virus after a 5-min contact time at high concentration, with maintenance of this activity after dilution (3h). A homogeneous antibacterial activity was observed on the resident flora.

CONCLUSION

These in vitro tests confirm the value of chlorhexidine lozenges in the treatment of upper respiratory tract infections such as sore throat.

Organosilylated complex [Eu(TTA)3(Bpy-Si)]: a bifunctional moiety for the engeneering of luminescent silica-based nanoparticles for bioimaging

A new highly luminescent europium complex with the formula [Eu(TTA)3(Bpy-Si)], where TTA stands for the thenoyltrifluoroacetone, (C4H3S)COCH2COCF3, chelating ligand and Bpy-Si, Bpy-CH2NH(CH2)3Si(OEt)3, is an organosilyldipyridine ligand displaying a triethoxysilyl group as a grafting function has been synthesized and fully characterized. This bifunctional complex has been grafted onto the surface of dense silica nanoparticles (NPs) and on mesoporous silica microparticles as well. The covalent bonding of [Eu(TTA)3(Bpy-Si)] inside uniform Stöber silica nanoparticles was also achieved. The general methodology proposed could be applied to any silica matrix, allowed high grafting ratios that overcome chelate release and the tendency to agglomerate. Luminescent silica-based nanoparticles SiO2-[Eu(TTA)3(Bpy-Si)], with a diameter of 28 ± 2 nm, were successfully tested as a luminescent labels for the imaging of Pseudomonas aeruginosa biofilms. They were also functionalized by a specific monoclonal antibody and subsequently employed for the selective imaging of Escherichia coli bacteria.

[Internal and external quality controls for Elisa techniques of aspergillosis serodiagnosis: proposals of the group "sérodiagnostic fongique" of the Société française de mycologie médicale]

In the end of May 2012, a meeting of the group "sérodiagnostic fongique" of the "Société française de mycologie médicale" had concerned quality controls to use, in particular, in the follow-up of Elisa techniques. A preliminary investigation showed that the internal quality controls (CIQ), according to the terms defined by the accreditation, were not systematically used. In June, was published the new guide of the COFRAC SH-GTA-06 on quality controls, this text being applicable on July 1st, 2012. It incited the working group to formulate proposals on the choice of the CIQ for antigen and antibody Elisa in the aspergillosis serodiagnosis. Informations on the external evaluations of the quality (EEQ) have also been given to better define for what we can expect from it. All these controls will allow every laboratory to better master the used techniques and their conditions of realization. A strengthened dialogue between the users and the manufacturers should incite these last actors to improve the supplied kits. It will drive later to an improvement of the reliability of the results obtained by these techniques and their interest in the aspergillosis diagnosis.

Production of L. pneumophila monospecies biofilms in a low-nutrient-concentration medium

In aquatic environments such as water distribution systems, Legionella pneumophila persistence is -correlated to the presence of a biofilm. The method described here permits the formation of a monospecies L. pneumophila biofilm in microplates, enabling the screening of multiple parameters. The culture medium used has a low nutrient concentration compared to the classical Buffered Yeast Extract culture medium. Hence, bacterial growth occurs in the sessile phase, allowing the formation of three-dimensional structures.