Annie Michel-Nguyen

Contribution of the (1→3)-β-d-Glucan Assay for Diagnosis of Invasive Fungal Infections

ABSTRACT Diagnosis of invasive fungal infection (IFI) remains a challenge. A retrospective study was performed on 279 patients at three French university hospitals to evaluate the performance of the (1→3)-β-d-glucan assay (BG assay; Fungitell; Associates of Cape Cod, Inc.) for the diagnosis of IFI. The results of one serum per subject were analyzed for 117 patients who had probable or proven IFI according to the European Organization for Research and Treatment of Cancer criteria (70 invasive pulmonary aspergilloses [IPA], 27 fungal bloodstream infections, and 20 Pneumocystis jiroveci pneumonias), 40 blood donors, and 122 patients who were hospitalized in hematology wards or intensive care units and were at risk for IFI but in whom IFI had not been diagnosed. For the overall IFI diagnosis, the BG assay had 77.8% sensitivity and specificities of 92.5 and 70.5% for blood donors and patients at risk, respectively. The assay was positive in 48 patients with IPA (68%), in 23 with bloodstream infections (85.2%), and in all who had P. jiroveci pneumonias (100%), and the false-positive rate varied depending on the controls used. It allowed a higher rate of detection among IPA patients compared to the galactomannan enzyme-linked immunosorbent assay (ELISA) (48 versus 39 patients, respectively) and among candidemia patients compared to the mannan ELISA (20 versus 11 patients, respectively). This assay therefore appears to be useful in the diagnosis of IFI, particularly for serum analysis of pneumocystosis pneumonia patients, but further studies are needed to evaluate false-positive rates and its future role in IFI diagnosis.

Colony morphology switching of Candida lusitaniae and acquisition of multidrug resistance during treatment of a renal infection in a newborn: case report and review of the literature.

Candida lusitaniae is an emerging opportunistic pathogen which exhibits an unusual antifungal susceptibility pattern. We describe a case of fatal renal infection due to C. lusitaniae in a very low birth weight neonate who was treated with short courses of fluconazole given alternately with amphotericin B. A colony morphology switching was detected on the standard primary culture medium by changes in colony size. Switching was shown to affect deeply the susceptibility to amphotericin B. Afterwards, the switched phenotype developed a cross resistance to fluconazole and itraconazole. Several issues raised by this case are discussed in the light of an extensive review of the literature. Our observations point out the importance of both the detection of colony morphology switching and the close monitoring of antifungal susceptibility in the management of infections due to C. lusitaniae. A judicious therapeutic strategy should prevent the acquisition of multidrug resistance during antifungal therapy.

Do the components of heat and moisture exchanger filters affect their humidifying efficacy and the incidence of nosocomial pneumonia

OBJECTIVES To compare the efficiency of two heat and moisture exchange filters (HMEFs) of different compositions of the humidifying capacity and the rate of bronchial colonization and ventilator-associated pneumonia in patients in the intensive care unit (ICU). DESIGN Prospective, randomized study. SETTING ICU of a university hospital. PATIENTS All patients who required mechanical ventilation for 24 hrs or more during the study period. INTERVENTIONS At admission to the ICU, patients were randomly assigned to one of two groups. In one group, the patients were ventilated with Humid-Vent Filter Light HMEF. The condensation surface was made of paper impregnated with CaCl2. The filter membrane was made of polypropylene. In the other group, the patients were ventilated with the Clear ThermAl HMEF (Intersurgical, France). The condensation surface was made of plastic foam impregnated with AlCl2. The filter membrane was made of two polymer fibers (modacrylic and polypropylene). In both groups, HMEFs were changed daily. MEASUREMENTS AND MAIN RESULTS Seventy-seven patients were ventilated for 19+/-7 days with the Humid-Vent Filter Light HMEF and 63 patients for 17+/-6 days with the Clear ThermAl HMEF. Patients ventilated with the Humid-Vent Filter Light underwent 8.7+/-3.7 tracheal aspirations and 1.2+/-2.0 instillations per day and those with the Clear ThermAl, 8.2+/-3.9 and 1.5+/-2.4 per day, respectively (NS). The abundance of tracheal secretions and the presence of blood and viscosity, as evaluated by semiquantitative scales, were similar in both groups. One episode of tracheal tube occlusion was observed with the Humid-Vent Filter Light HMEF and none with the other HMEF (NS). Tracheal colonization was observed at a rate of 91% with the Humid-Vent Filter Light and 97% with the Clear ThermAl (NS). The rate of ventilator-associated pneumonia was similar in both groups (35%). Bacteria responsible for tracheal colonization and pneumonia were similar in both groups. CONCLUSIONS Despite differences in their components, the two HMEFs that were tested achieved similar performances in terms of humidification and heating of inspired gases. Only one episode of endotracheal tube occlusion was detected, and very few patients (three in each group) had to be switched to an active heated humidifier. No difference was observed either in the rate of tracheal colonization or of ventilator-associated pneumonia. These data show that the Humid-Vent Filter Light and the Clear ThermAl HMEFs are suited for use with ICU patients.

Interactions between copy number and expression level of genes involved in fluconazole resistance in Candida glabrata

Objectives: This study aimed to elucidate the relative involvement of drug resistance gene copy number and overexpression in fluconazole resistance in clinical C. glabrata isolates using a population-based approach. Methods: Fluconazole resistance levels were quantified using the minimal inhibitory concentration (MIC) via Etest method. Both gene expression levels and gene copy number of CgCDR1, CgPDH1, CgERG11, and CgSNQ2 were assessed via quantitative real-time PCR. The influence of the main effects and first-level interactions of both the expression level and copy number of these genes on fluconazole resistance levels were analyzed using a multivariate statistical model. Results: Forty-three C. glabrata isolates were collected from 30 patients during in a hospital survey. In the multivariate analysis, C. glabrata fluconazole MICs were independently increased by CgSNQ2 overexpression (p < 10−4) and the interaction between CgPDH1 gene copy number and CgPDH1 expression level (p = 0.038). In contrast, both CgPDH1 overexpression (p = 0.049) and the interaction between CgSNQ2 and CgERG11 expression (p = 0.003) led to a significant decrease in fluconazole MICs. Conclusion: Fluconazole resistance in C. glabrata involves complex interactions between drug resistance gene expression and/or copy number. The population-based multivariate analysis highlighted the involvement of the CgSNQ2 gene in fluconazole resistance and the complex effect of the other genes such as PDH1 for which overexpression was associated with reduced fluconazole resistance levels, while the interaction between PDH1 overexpression and copy number was associated with increased resistance levels.

Differentiation between Atypical Isolates of Candida lusitaniae and Candida pulcherrima by Determination of Mating Type

ABSTRACT We report on five clinical isolates routinely identified as Candida lusitaniae that the ID 32C system was unable to discriminate from the closely related species Candida pulcherrima. When additional tests did not allow accurate identification, the less usual mating type test identified all of them as Clavispora lusitaniae. Mating type testing appears to be a valuable tool for assessing the true incidence of this emerging non-albicans Candida species.

Trailing or paradoxical growth of Candida albicans when exposed to caspofungin is not associated with microsatellite genotypes.

ABSTRACT Multilocus microsatellite polymorphisms in 27 clinical Candida albicans isolates were found to be clearly unrelated to in vitro paradoxical growth or trailing effect with caspofungin. These findings suggest that such in vitro phenotypes are either gained or lost too rapidly to be predicted by more stable genomic markers.

H-08 Champignons isolés d’hémocultures au CHU de Marseille

Objectif Decrire l’epidemiologie des champignons isoles d’hemocultures a l’Assistance Publique-Hopitaux de Marseille d’octobre 2005 a fevrier 2008. Resultats De 444 hemocultures issues de 230 patients (presentant 1 a 20 hemocultures positives) 16 especes differentes ont ete identifiees et 18 patients avaient plus d’une espece de champignon dans au moins une hemoculture. La repartition par groupe de service des differentes especes impliquees dans une fongemie figure dans le tableau ci-dessous. Conclusion Ces donnees refletent l’heterogeneite de l’epidemiologie des champignons isoles en fonction du service. C. albicans reste l’espece predominante mais sa frequence est C. parapsilosis ou C. glabrata , selon les services, se situent au second rang avec une frequence d’environ 20 %. Le groupe « Autres » constitue de neuf especes, chacune rarement isolee, est au cinquieme rang, totalisant 8 % des fongemies. Champignon n (%) Chirurgie Medecine Onco-Hematologie Reanimation Pediatrie Total Candida albicans 13 (52) 40 (51) 40 (52) 16 (30) 6 (43) 115 (46) Candida parapsilosis 5 (20) 3 (4) 14 (18) 6 (11) 3 (21) 40 (16) Candida glabrata 4 (16) 15 (19) 4 (5) 7 (13) 1 (7) 31 (13) Candida tropicalis 1 (4) 4 (5) 10 (13) 7 (13) 1 (7) 23 (9) Candida krusei 0 (0) 1 (1) 1 (1) 5 (9) 0 (0) 7 (3) Saccharomyces sp. 1 (4) 0 (0) 0 (0) 6 (11) 0 (0) 7 (3) C. neoformans 0 (0) 3 (4) 0 (0) 1 (2) 1 (7) 5 (2) Autres * 1 (4) 13 (16) 8 (11) 5 (9) 2 (14) 20 (8) Total 25 (10) 79 (32) 77 (31) 53 (21) 14 (6) 248 (100) * : C. dubliniensis, C. famata, C. guilliermondii, C. inconspicua, C. kefyr, C. lipolytica, C. lusitaniae, Fusarium sp., G. capitatum.