P. Le Pape

Is real-time PCR-based diagnosis similar in performance to routine parasitological examination for the identification of Giardia intestinalis, Cryptosporidium parvum/Cryptosporidium hominis and Entamoeba histolytica from stool samples? Evaluation of a new commercial multiplex PCR assay and literature review

Microscopy is the reference standard for routine laboratory diagnosis in faecal parasitology but there is growing interest in alternative methods to overcome the limitations of microscopic examination, which is time-consuming and highly dependent on an operators skills and expertise. Compared with microscopy, DNA detection by PCR is simple and can offer a better turnaround time. However, PCR performances remain difficult to assess as most studies have been conducted on a limited number of positive clinical samples and used in-house PCR methods. Our aim was to evaluate a new multiplex PCR assay (G-DiaParaTrio; Diagenode Diagnostics), targeting Giardia intestinalis, Cryptosporidium parvum/Cryptosporidium hominis and Entamoeba histolytica. To minimize the turnaround time, PCR was coupled with automated DNA extraction (QiaSymphony; Qiagen). The PCR assay was evaluated using a reference panel of 185 samples established by routine microscopic examination using a standardized protocol including Ziehl-Neelsen staining and adhesin detection by ELISA (E. histolytica II; TechLab). This panel, collected from 12 French parasitology laboratories, included 135 positive samples for G. intestinalis (n = 38), C. parvum/C. hominis (n = 26), E. histolytica (n = 5), 21 other gastrointestinal parasites, together with 50 negative samples. In all, the G-DiaParaTrio multiplex PCR assay identified 38 G. intestinalis, 25 C. parvum/C. hominis and five E. histolytica leading to sensitivity/specificity of 92%/100%, 96%/100% and 100%/100% for G. intestinalis, C. parvum/C. hominis and E. histolytica, respectively. This new multiplex PCR assay offers fast and reliable results, similar to microscopy-driven diagnosis for the detection of these gastrointestinal protozoa, allowing its implementation in routine clinical practice.

Azole Resistance in Aspergillus fumigatus in Patients with Cystic Fibrosis: A Matter of Concern?

Aspergillus fumigatus is the most frequent filamentous fungus isolated from respiratory specimens from patients with cystic fibrosis (CF). Triazoles are the most widely used antifungals in the treatment of allergic bronchopulmonary aspergillosis (ABPA) and invasive aspergillosis (IA) in CF patients. Treatment success could be severely compromised by the occurrence of azole-resistant A. fumigatus (ARAf), which is increasingly reported worldwide from both clinical samples and the environment. In previous studies, ARAf has been detected in up to 8% of CF patients. Isolates from CF patients requiring antifungal treatment should therefore be routinely subjected to antifungal susceptibility testing. The optimal treatment of ABPA or IA in CF patients with azole-resistant isolates has not been established; treatment options include liposomal amphotericin B i.v. and/or echinocandins i.v.

Multifocal phaeohyphomycosis caused by Exophiala xenobiotica in a kidney transplant recipient.

In recent years, black fungi have been increasingly reported as causing opportunistic infections after solid organ transplantation. Here, we report a case of insidious, relentless, and multifocal Exophiala xenobiotica infection in a kidney transplant recipient that eventually required multiple surgical excisions along with oral and intravenous antifungal combination therapy using liposomal amphotericin B and posaconazole. We compare the present case with all previously reported cases of Exophiala infection after kidney transplantation.

Prévalence de Candida parapsilosis, C. orthopsilosis et de C. metapsilosis au sein des candidémies au CHU de Nantes et profil de sensibilité aux échinocandines par la méthode E-test® : étude rétrospective de cinq ans (2004–2009)Prevalence of Candida parapsilosis, C. orthopsilosis and C. metapsilosis in candidemia over a 5-year period at Nantes hospital and in vitro susceptibility to three echinocandins by E-test®

AIM OF THE STUDY To determine the prevalence of C. parapsilosis sensu stricto, C. orthopsilosis and C. metapsilosis among candidemia at Nantes University Hospital and to evaluate the in vitro susceptibility of the isolates against three echinocandin drugs (caspofungin, micafungin and anidulafungin). MATERIAL AND METHODS Retrospective study (march 2004 to july 2009) of 178 cases of candidemia corresponding to 183 Candida spp. strains identified by means of routine phenotypical methods. Re-identification of C. parapsilosis sensu lato isolates was performed by ITS rDNA sequencing analysis. Minimal inhibitory concentrations (MIC) were determined by E-test(®). All echinocandin non-susceptible isolates (MIC>2 μg/mL) were analyzed for the presence/absence of FKS1 mutations associated with resistance. RESULTS During this period, C. parapsilosis sensu lato was responsible for 27 candidemia, ranging at the second most common Candida species after C. albicans (n=99, 54.1%). Neither isolates belong to C. orthopsilosis nor C. metapsilosis. According to the literature, all the isolates displayed high MICs against the three echinocandin drugs. All the isolates displayed both susceptibility (MIC ≤ 2 μg/mL) and a good agreement between MICs read at 24h and 48 h for caspofungin and micafungin (MIC(50)=0.75 μg/mL, MIC(90)=1.5 μg/mL). Surprisingly, whereas most of the strains were susceptible to anidulafungin at 24h (MIC(50)=1 μg/mL, MIC(90)=1.5 μg/mL), 14 (52 %) displayed non-susceptibility, despite the lack of mutation associated with resistance on FKS1, when reading was performed at 48 h (MIC(50)=3 μg/mL, MIC(90)=12 μg/mL). CONCLUSION Prevalence of C. orthopsilosis and C. metapsilosis in patients with candidemia is low at Nantes University Hospital. The difficulty encountered with MIC reading by E-test(®) are discussed.

Prévalence de Candida parapsilosis , C. orthopsilosis et de C. metapsilosis au sein des candidémies au CHU de Nantes et profil de sensibilité aux échinocandines par la méthode E-test ® : étude rétrospective de cinq ans (2004–2009)

AIM OF THE STUDY To determine the prevalence of C. parapsilosis sensu stricto, C. orthopsilosis and C. metapsilosis among candidemia at Nantes University Hospital and to evaluate the in vitro susceptibility of the isolates against three echinocandin drugs (caspofungin, micafungin and anidulafungin). MATERIAL AND METHODS Retrospective study (march 2004 to july 2009) of 178 cases of candidemia corresponding to 183 Candida spp. strains identified by means of routine phenotypical methods. Re-identification of C. parapsilosis sensu lato isolates was performed by ITS rDNA sequencing analysis. Minimal inhibitory concentrations (MIC) were determined by E-test(®). All echinocandin non-susceptible isolates (MIC>2 μg/mL) were analyzed for the presence/absence of FKS1 mutations associated with resistance. RESULTS During this period, C. parapsilosis sensu lato was responsible for 27 candidemia, ranging at the second most common Candida species after C. albicans (n=99, 54.1%). Neither isolates belong to C. orthopsilosis nor C. metapsilosis. According to the literature, all the isolates displayed high MICs against the three echinocandin drugs. All the isolates displayed both susceptibility (MIC ≤ 2 μg/mL) and a good agreement between MICs read at 24h and 48 h for caspofungin and micafungin (MIC(50)=0.75 μg/mL, MIC(90)=1.5 μg/mL). Surprisingly, whereas most of the strains were susceptible to anidulafungin at 24h (MIC(50)=1 μg/mL, MIC(90)=1.5 μg/mL), 14 (52 %) displayed non-susceptibility, despite the lack of mutation associated with resistance on FKS1, when reading was performed at 48 h (MIC(50)=3 μg/mL, MIC(90)=12 μg/mL). CONCLUSION Prevalence of C. orthopsilosis and C. metapsilosis in patients with candidemia is low at Nantes University Hospital. The difficulty encountered with MIC reading by E-test(®) are discussed.

Multicenter Comparison of the Etest and EUCAST Methods for Antifungal Susceptibility Testing of Candida Isolates to Micafungin

ABSTRACT In vitro susceptibility of 933 Candida isolates, from 16 French hospitals, to micafungin was determined using the Etest in each center. All isolates were then sent to a single center for determination of MICs by the EUCAST reference method. Overall essential agreement between the two tests was 98.5% at ±2 log2 dilutions and 90.2% at ±1 log2 dilutions. Categorical agreement was 98.2%. The Etest is a valuable alternative to EUCAST for the routine determination of micafungin MICs in medical mycology laboratories.

A 3D-QSAR CoMSIA study on 3-azolylmethylindoles as anti-leishmanial agents

A three-dimensional quantitative structure-activity relationship (3D-QSAR) study using Comparative Molecular Similarity Indices Analysis (CoMSIA) was conducted on a series of 3-azolylmethylindoles as anti-leishmanial agents. Evaluation of 24 compounds synthesized in our laboratory served to establish the model. A random search was performed on the library of compounds, and molecules of the training set were aligned on common elements of template molecule 13, one of the most active compounds. The best predictions were obtained from multifit procedure with a CoMSIA model combining steric, electrostatic, hydrophobic and hydrogen bond acceptor fields (q 2 = 0.594, r 2 = 0.897). The model was validated using an external test set of 7 compounds giving a satisfactory predictive r 2 value of 0.649. Information obtained from CoMSIA contour maps could be used for further design of more promising inhibitors.