Biomedical subjects

F Dalle

Publications and source records attributed to F Dalle.

5 recordsLinked to original sources

PubMed2002

False-positive results caused by cotton swabs in commercial Aspergillus antigen latex agglutination test.

While testing for Aspergillus spp. using a commercially available latex agglutination test on a brain biopsy wrapped in a cotton swab, false-positive results were obtained. Subsequent application of the test on lavage samples obtained using cotton and synthetic swabs resulted positive with the cotton swabs only. This suggests that epitopes cross-reactive with Aspergillus galactomannan may be present in cotton.

Antigens, Fungal↗

PubMed2001

Decrease in Candida albicans strains with reduced susceptibility to fluconazole following changes in prescribing policies.

This study was undertaken to identify prescribing policies likely to favour or limit fluconazole resistance within a clinical department. Fluconazole exposure within the infectious diseases and clinical haematology units was investigated, and data were compared with in vitro susceptibility of Candida albicans isolates obtained in these units. Fluconazole utilization was determined by the number of fluconazole treatment-days per 100 hospitalization days (penetration index). In the infectious diseases unit, separate evaluations for low-dose fluconazole (50 mg) prescribed as intermittent or prolonged treatment, and for higher-dosing schedules (fluconazole 200 mg) were made. Susceptibility of C. albicans isolates was surveyed in a broth microdilution assay by measuring the inhibitory concentration 50% (IC50). The penetration index (PI) for fluconazole 50mg declined from 1992 to 1977 in infectious diseases (P= 0.0048). In the meantime, total usage of fluconazole increased, due to increased prescribing of fluconazole 200 mg (P = 0.0724). The IC50 of C. albicans isolates tested in infectious diseases decreased between 1994 and 1996 from 7.33 mg/ml to 1.64 mg/ml (P = 0.0075). In clinical haematology, declines in C. albicans IC50 and fluconazole PI were not significant (P = 0.35 and P = 0.07, respectively). These data suggest that prolonged or repeated exposure to low-dose fluconazole, rather than total cumulative use, was associated with fluconazole resistance in the infectious diseases unit. Moreover, restoration of a normal ecology was observed when low-dose prolonged or intermittent prescriptions were reduced.

Analysis of Variance↗

PubMed2001

Rapid identification of Candida glabrata based on trehalose and sucrose assimilation using Rosco diagnostic tablets.

We developed a simple method for the identification of Candida glabrata on the basis of the ability of this species to rapidly assimilate trehalose but not sucrose. After incubation of yeasts with Rosco diagnostic tablets containing sucrose or trehalose, identification of C. glabrata was achieved in 4 h with 100% sensitivity and specificity.

Candida↗

PubMed2000

Comparative genotyping of Candida albicans bloodstream and nonbloodstream isolates at a polymorphic microsatellite locus.

Molecular typing studies have shown that the predominant form of reproduction of Candida albicans is clonal and that, in a majority of situations, persistent or recurrent infections are due to a unique strain. Characterization of distinct subpopulations and correlation with clinical features may thus be important to understanding the pathogenesis of candidiasis. In a clonal model, a unique polymorphic marker may identify populations with different biological properties. We therefore compared 48 bloodstream isolates and 48 nonbloodstream matched strains of C. albicans at the elongation factor 3-encoding gene (CEF3) polymorphic microsatellite locus of C. albicans. Sizing of the alleles was performed by automated capillary electrophoresis. A new, 137-bp allele was characterized, and seven nondescribed combinations were observed, resulting in 15 and 11 distinct CEF3 profiles in bloodstream and control strains, respectively. Genotypes 126-135, 130-136, and 131-131 accounted for 60.4% of both bloodstream and control strains. Four bloodstream isolates but no control strains displayed the 135-135 combination. None of the other genotypes was present at an increased frequency in bloodstream isolates. Bloodstream and nonbloodstream strains of C. albicans thus have a heterogeneous structure at the CEF3 locus, with three major and multiple minor allelic combinations.

Alleles↗

PubMed1998

Experimental efficacy of combined ceftriaxone and amoxycillin on penicillin-resistant and broad-spectrum cephalosporin-resistant Streptococcus pneumoniae infection.

The activity of amoxycillin and ceftriaxone, alone and in combination, was tested against four strains of penicillin-resistant pneumococci in vitro and in an animal model. Three of the strains were also resistant to third-generation cephalosporins. Fractional inhibitory concentration indexes for combined amoxycillin and ceftriaxone were measured by the Etest method and were considered additive (1.2; 1.1; 1.3 and 1.3 for the four strains). Twenty-four hour time-kill curves for two strains showed that the combination was additive or synergic for concentrations up to the MIC of the single drugs. The efficacy of these antibiotics alone and in various combinations against strains 16089 and 11724 were investigated in vivo using prolonged (48 h) experimental fibrin clot infection in rabbits. The bacterial reductions (delta log10 cfu/g) obtained for all the antibiotic combinations tested were significantly higher than those of the single drug regimens. The in-vivo efficacy of amoxycillin was significantly correlated with the time for which its concentration was above the MIC and that of ceftriaxone was correlated with its maximal concentration. From these findings, we concluded that, at concentrations easily achievable in humans, the combination of amoxycillin and ceftriaxone was strongly synergic against infection due to penicillin- and cephalosporin-resistant pneumococci.

Amoxicillin↗