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See detailComparison of the Sensititre YeastOne and Fungitest methods with the NCCLS M27-A2 reference method for antifungal susceptibility testing of yeasts
Hayette, Marie-Pierre ULg; Kondarowski, E.; Melin, Pierrette ULg et al

Poster (2005, December)

Background: The recent introduction of Sensititre YeastOne, a colorimetric microdilution method that includes new antifungal agents has opened the field to MIC’s determination by an easy-to-perform method ... [more ▼]

Background: The recent introduction of Sensititre YeastOne, a colorimetric microdilution method that includes new antifungal agents has opened the field to MIC’s determination by an easy-to-perform method. The aim of this study was to compare this test with the NCCLS M27-A protocol and with Fungitest, a current routine method for yeasts susceptibility testing. Methods: Sensititre YeastOne method (Trek diagnostic), and the NCCLS M27-A2 were performed on 300 yeasts clinical isolates distributed as follow: 125 C. albicans, 273 non-albicans species. Four antifungal agents were tested by the reference method: amphotericine B (AmB), fluconazole (FZ), itraconazole (ITZ), and voriconazole (VOR). The reading of the Sensititre and NCCLS results was visually performed after 24 and 48 h respectively. The Fungitest (Biorad) method was applied on 121 among the 300 isolates and the reading was made after 24 to 48 h incubation time according to the positive control growth. Results: By the NCCLS method, the MICs50/MICs90 (µg/ml) were as follows: 1/2 (AmB); 16/64 (FZ); 0.25/4 (ITZ) and 0.125/2 (VOR). Sensititre vs. NCCLS: The overall agreement within 2 dilutions for AmB, FZ, ITZ and VOR was respectively 54, 82, 80 and 78%. The MICs50/MICs90 were in absolute concordance for VOR by both techniques. Very major errors (%) were recorded as follows: 0.01/0 (AmB with a MIC ≥ 4/8µg/ml for resistant strains respectively), 1.6 (FZ), 3.6 (ITZ) and 2.3 (VOR with a MIC ≥ 8µg/ml for resistant strains). Fungitest vs. NCCLS: The agreement between both methods including minor discrepancies was 98% (AmB), 88% (FZ) and 98% (ITZ). Following the breakpoints given by the manufacturer, very major errors were 6.3% for FZ, 0.03% for ITZ and none for AmB. Conclusions: Sensititre is a convenient alternative to the NCCLS method for yeast susceptibility testing. Fungitest in spite of good correlations must change the breakpoints and include new antifungal agents to be competitive. [less ▲]

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See detailPrevalence of ermB, ermTR and mefA/B gene classes among erythromycine resistant group B streptococcus isolates collected in Belgium
MELIN, Pierrette ULg; Rodriguez Cuns, Grisel; Tsobo, Chantal et al

Poster (2001, October)

Background: Emergence of erythromycin (Er) and clindamycin (C) resistance (R) observed in GBS, is currently becoming recognized. Methods: Clinical isolates were obtained from a Belgian surveillance for ... [more ▼]

Background: Emergence of erythromycin (Er) and clindamycin (C) resistance (R) observed in GBS, is currently becoming recognized. Methods: Clinical isolates were obtained from a Belgian surveillance for invasive GBS disease in newborns and adults in 1996-1998 (N1=235) and from consecutive specimens submitted, during 1999-2000, to the University hospital of Liege (N2=165). MICs of Er were determined buy using Etest® strip (interpretive criteria of NCCLS). Furthermore, for the ErR isolates, the inducible (iMLS), constitutive (cMLS) and M phenotypes were assessed by disk diffusion and by a double-disk test; the distribution of genes encoding RNA methylases and efflux pumps was investigated by PCR. Results: Of the N1 and N2 isolates, 16 (6.8%) and 19 (11.5%) were respectively R to Er. Among these 35 ErR isolates, 21 (60%) exhibited the cMLS phenotype. They demonstrated a high level R to Er with MICs ranging from 16 to >256 mg/L. The ermB gene was harbored by 19/21 isolates, the ermTR gene by 1 isolate and both ermB and ermTR were present in another isolate. The iMLS phenotype was observed in 10 (29%) ErR isolates; the ermTR gene was present in all isolates except one harboring an ermTR gene. These strains demonstrated low level of R to Er, with MICs of 1-12 mg/L. All 4 isolates (11%) expressing an M phenotype, displayed low level R to Er alone (MICs, 2 mg/L) and were positive for the mefA/B gene. Conclusion: In Belgium, by year 2000, prevalence of R to macrolide in GBS exceeded 10%. R was mainly caused by target-site modification (ermB, ermTR) mechanisms; efflux (mefA/B) R mechanism was also prevalent among the isolates tested. These results indicate the possibility of inappropriate prophylaxis or therapy using C or E as the recommended alternatives in penicillin-allergic patients. [less ▲]

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See detailRapid intrapartum test (Strep B OIA) and prenatal cultures for identification of group B streptococcal carriers at delivery: a prospective study
MELIN, Pierrette ULg; Schmitz, Myriam; Tsobo, Chantal et al

in AAmerican Society of Microbiology (Ed.) Program and Abstracts of the 40th Intersciences Conference on Antimicrobial Agents and Chemotherapy (2000, September)

Background: The efficacy of the prenatal screening-based approach recommended by the CDC to prevent neonatal GBS diseases could be improved by using a good rapid test performed at the onset of labor. To ... [more ▼]

Background: The efficacy of the prenatal screening-based approach recommended by the CDC to prevent neonatal GBS diseases could be improved by using a good rapid test performed at the onset of labor. To assess the Strep B OIA® test (Biostar, Boulder, Co), completed in 30 minutes, we initiated a 6-center study to compare it with prenatal screening cultures to identify GBS carriers at delivery or opportunities to initiate intrapartum antibioprophylaxis (IAP). Methods: For a total of 539 pregnant women included in the study, pairs of vaginal/anal specimens collected at 35-37 weeks and intrapartum vaginal specimens were plated onto colistin-nalidixic agar and then inoculated into selective LIM broth for the detection of GBS. Furthermore, on each intrapartum vaginal swab a Strep B OIA test was performed. Results: GBS were recovered in culture from 89 prenatal screenings (17%) and from 71 specimens collected at delivery (13%). Strep B OIA test identified 48 positive specimens (9%). Respectively, for the identification of GBS carriers at delivery, sensitivity, specificity, positive and negative predictive values for prenatal screening cultures were 69%, 91%, 55% and 95% and for Strep B OIA tests they were 63%, 99%, 94% and 95%. Evaluating opportunities to start an IAP, based on Strep OIA test versus prenatal screening cultures, 45 IAP vs. 49 would have been useful, 3 vs. 40 useless (P< 0,001) and 26 vs. 22 missed. Conclusion: To identify GBS carriers, the Strep B OIA test, performed at the time of onset of labor is equally sensitive to prenatal screening cultures and would allow a highly significant reduction of useless IAP. [less ▲]

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