Azole-resistant Aspergillus fumigatus in sawmills of Eastern France.

AIMS: Emergence of azole-resistant Aspergillus fumigatus complicates management of Aspergillus diseases. Currently, selection pressure caused by azole fungicide use in farming is strongly suspected of creating resistance. As sawmills also use azole fungicides, we investigated the presence of azole-resistant strains in this environment and studied the relationship between azole fungicide use and development of resistance. METHODS AND RESULTS: Air (n = 200) and substrate (n = 600) samples were taken in 20 sawmills. Azole-resistant strains (Etest and EUCAST methods) were confirmed by sequencing the cyp51A gene and its promoters. Dosage of propiconazole and tebuconazole was performed by gas chromatography coupled with mass spectrometry. Twenty-four azole-resistant A. fumigatus strains were collected among 20 of the 600 substrate samples (3%). Eighty-three percent of theses strains had TR34 /L98H mutation. A significantly higher number of resistant strains was collected in sawmills using fungicide products made with propiconazole mixed with a high concentration of tebuconazole (P = 0·009). The presence of resistant strains was significantly linked to propiconazole quantities in substrates (P = 0·03). CONCLUSIONS: The outcome of azole-resistant A. fumigatus carrying TR34 /L98H mutation seems to greatly depend on the azole fungicide formulation and quantities of azole. These preliminary results are valuable to propose new approaches limiting the emergence of azole-resistant strains. SIGNIFICANCE AND IMPACT OF THE STUDY: Azole resistance is an emerging problem in A. fumigatus and threatens clinical advances made possible by the use of azole antifungals in the treatment of Aspergillus-related diseases. Azole fungicides are also used in the wood industry, notably in sawmills, to protect wood from wood-destroying fungi. Through our study, we show that sawmills represent another professional environment affected by the presence of azole-resistant A. fumigatus strains carrying the TR34 /L98H mutation. Moreover, this study provides valuable preliminary results to propose some new approaches to limit the emergence of azole-resistant A. fumigatus strains.

Allylamine-beta-cyclodextrin copolymer. A novel chiral selector for capillary electrophoresis.

A novel, positively charged, copolymer of allylamine and 2-hydroxy-3-methacryloyl-beta-cyclodextrin was synthesized to be used as a chiral selector in capillary electrophoresis. In the copolymer, cyclodextrin molecules are spaced from the backbone though a spacer arm which prevents sterical hindrance of the CD cavity. The self-mobility of the CD polymer in its charged form, opposite to the analytes, is the cause for the enhanced separation factor provided by this selector. Moreover, the positive charged polymer induces a reversal of electroosmotic flow which is beneficial in enantioseparations of acidic compounds as it reduces analysis time and increases peak efficiency. The ability of this copolymer to act as a CE chiral selector in the separation of 2,4-dinitrophenylamino acid enantiomers was investigated in coated and uncoated capillaries and its performance was much better then that of native beta-cyclodextrin.

Vinylpyrrolidine-beta-cyclodextrin copolymer: a novel chiral selector for capillary electrophoresis.

The synthesis and characterization of a novel polymer consisting of an alkyl backbone and pendant beta-cyclodextrin units, obtained by radical copolymerization of vinylpyrrolidone and methacryloyl-beta-cyclodextrin (PVP-beta-CD), was reported. The ability of this copolymer to act as a capillary electrophoresis (CE) chiral selector was investigated in the separation of a mixture of basic drugs. The influence of polymeric cyclodextrin concentration, temperature, and pH on the separation of the test analytes was assessed and the advantage of using the polymeric selector over native beta-cyclodextrin was demonstrated.

Solid state NMR spectroscopy study of molecular motion in cyclomaltoheptaose (beta-cyclodextrin) crosslinked with epichlorohydrin.

Dry and hydrated insoluble cyclomaltoheptaose (beta-cyclodextrin, beta-CD) polymers have been investigated by solid state 13C NMR spectroscopy techniques such as cross polarization/magic angle spinning with dipolar decoupling (CP/MAS), magic angle spinning both with (DD-MAS) and without (MAS) dipolar decoupling and CP/MAS dipolar dephasing (dd-CP/MAS) to allow the assignment of the main 13C signals. In the solid state, the presence of water in the samples resulted in a better resolution reflecting increased mobility. Two distinct components (crosslinked beta-CD and polymerized epichlorohydrin) have been found. The molecular mobility of these two components has been analyzed in terms of relaxation parameters such as 13C spin lattice relaxation (T1) and 1H spin lattice relaxation in the rotating frame (T1 rho). The T1 values of the polymers show that the beta-CD trapped inside the polymers does not seem to undergo changes in its mobility whatever the amount of epichlorohydrin. The addition of water to beta-CD significantly increases the T1 values reflecting strong interaction between beta-CD and the solvent. The T1P values obtained reflect the homogeneous nature of the materials.

HPLC of structural isomers with cyclodextrin-poly(vinylamine)-coated silica columns, Part I: Synthesis and characterization of cyclodextrin-bonded stationary phases by NMR solid state.

Different supports for high-performance liquid chromatography are prepared by using the coating technology. These supports are based on silica beads coated with a beta-cyclodextrin-containing poly(vinylamine). Surface area, pore size distribution, and solid-state nuclear magnetic resonance are used for the characterization of these supports. The two different methods of preparation used lead to different arrangements of the polymer layers; hence, the supports have different mobility, rigidity, and accessibility of the cyclodextrin ring.