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Effects of Voriconazole on Cryptococcus neoformans. David van Duin, 2004.Voriconazole is a broad-spectrum triazole that offers extended activity against molds and yeasts that are not susceptible to earlier azole-type drugs . Recent studies indicate that melanization can severely reduce the susceptibility of certain antifungal drugs, but there is no information as to whether voriconazole is vulnerable to this effect . The activity of voriconazole on C . neoformans was assessed by MIC analysis and time-kill assays for melanized and nonmelanized cells . Cell morphology, capsule release, and phagocytosis of C . neoformans were studied in the presence or absence of subinhibitory concentrations of voriconazole . Voriconazole was fungicidal at concentrations of  8 µg/ml in vitro against the strains of C . neoformans examined, and its efficacy was not diminished by melanization . Cells grown in subinhibitory concentrations of voriconazole had smaller cellular and capsular volumes than cells grown in the absence of drug . The induction of the capsule by serum was not affected by voriconazole . Cells grown in subinhibitory concentrations of voriconazole released their capsule and were phagocytosed at rates comparable with yeast grown without the antifungal . The high activity of voriconazole against both melanized and nonmelanized cells results suggest that voriconazole may be a particularly valuable drug for cryptococcosis .
Molecular Fingerprinting of Dairy Microbial Ecosystems by Use of Temporal Temperature and Denaturing Gradient Gel Electrophoresis. J.-C. Ogier, 2004.Numerous microorganisms, including bacteria, yeasts, and molds, constitute the complex ecosystem present in milk and fermented dairy products . Our aim was to describe the bacterial ecosystem of various cheeses that differ by production technology and therefore by their bacterial content . For this purpose, we developed a rapid, semisystematic approach based on genetic profiling by temporal temperature gradient electrophoresis (TTGE) for bacteria with low-G+C-content genomes and denaturing gradient gel electrophoresis (DGGE) for those with medium- and high-G+C-content genomes . Bacteria in the unknown ecosystems were assigned an identity by comparison with a comprehensive bacterial reference database of  150 species that included useful dairy microorganisms (lactic acid bacteria), spoilage bacteria (e.g., Pseudomonas and Enterobacteriaceae), and pathogenic bacteria (e.g., Listeria monocytogenes and Staphylococcus aureus) . Our analyses provide a high resolution of bacteria comprising the ecosystems of different commercial cheeses and identify species that could not be discerned by conventional methods; at least two species, belonging to the Halomonas and Pseudoalteromonas genera, are identified for the first time in a dairy ecosystem . Our analyses also reveal a surprising difference in ecosystems of the cheese surface versus those of the interior; the aerobic surface bacteria are generally G+C rich and represent diverse species, while the cheese interior comprises fewer species that are generally low in G+C content . TTGE and DGGE have proven here to be powerful methods to rapidly identify a broad range of bacterial species within dairy products .
Survival of Bacterial Indicator Species and Bacteriophages after Thermal Treatment of Sludge and Sewage. Laura Mocé-Llivina, 2003.The inactivation of naturally occurring bacterial indicators and bacteriophages by thermal treatment of a dewatered sludge and raw sewage was studied . The sludge was heated at 80°C, and the sewage was heated at 60°C . In both cases phages were significantly more resistant to thermal inactivation than bacterial indicators, with the exception of spores of sulfite-reducing clostridia . Somatic coliphages and phages infecting Bacteroides fragilis were significantly more resistant than F-specific RNA phages . Similar trends were observed in sludge and sewage . The effects of thermal treatment on various phages belonging to the three groups mentioned above and on various enteroviruses added to sewage were also studied . The results revealed that the variability in the resistance of phages agreed with the data obtained with the naturally occurring populations and that the phages that were studied were more resistant to heat treatment than the enteroviruses that were studied . The phages survived significantly better than Salmonella choleraesuis, and the extents of inactivation indicated that naturally occurring bacteriophages can be used to monitor the inactivation of Escherichia coli and Salmonella .
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