Evaluation of a Prototype of a Novel Galactomannan Sandwich Assay Using the VIDAS® Technology for the Diagnosis of Invasive Aspergillosis.

Objectives: To evaluate the analytical and clinical performance of a prototype of a VIDAS® Galactomannan (GM) unitary test (bioMérieux, Marcy l'Etoile, France) and compare to that of the Platelia™ Aspergillus Ag assay (Bio-Rad, CA, USA). Methods: Repeatability, reproducibility, and freeze-thaw stability of VIDAS®GM were evaluated. Sera from patients at risk of IA were concurrently tested with both the VIDAS®GM and Platelia™ Aspergillus Ag assays. Correlations between the two assays were assessed by Passing Bablok (PB) regression and performance by ROC analysis. Results: The correlations between the VIDAS®GM indexes after one and two cycles of freezing/thawing were r=1.00 and r=0.989, respectively. The coefficients of variation for negative, low-positive, and positive sera were 13%, 6%, and 5% for repeatability and 14.4%, 7.2%, and 5.5% for reproducibility. Overall, 126 sera were tested with both assays (44 fresh and 82 frozen). The correlation between VIDAS®GM and Platelia™ Aspergillus Ag was r=0.798. The areas under the curve of the ROC analyses were 0.892 and 0.894, for VIDAS®GM and Platelia™ Aspergillus Ag, respectively. Conclusions: This new VIDAS®GM prototype assay showed adequate analytical and clinical performance and a good correlation with that of Platelia™ Aspergillus Ag with 126 sera, although these results need to be confirmed in a larger prospective and multicentric study. As for the other VIDAS® assays, VIDAS®GM is a single-sample automated test using a solid reagent strip and receptacle. It is easy to use and suitable for rapid on-demand test results.

Dermatophytes and Dermatophytosis in Cluj-Napoca, Romania-A 4-Year Cross-Sectional Study.

Dermatophytes are filamentous keratinophilic fungi which affect nails, skin, and hair. Their variable distribution in the world justifies local epidemiological studies. During recent decades, few studies have been published regarding the epidemiology and etiology of dermatophytosis in Romania. The aim of this study was to identify the dermatophytes isolated from superficial fungal infections. To the best of our knowledge, this is the first such study conducted in the area of North-Western Romania. Over the past four years, samples collected from outpatients with suggestive lesions for dermatophytoses (nails, skin, hair), who addressed several private practice dermatologists from Cluj-Napoca, Romania, were sent to a specialized laboratory and examined by microscopy and culture. A total of 350 samples from 322 patients were examined. One hundred samples (28.6%) collected from 90 patients (27.9%) were positive by direct microscopy and/or culture. Among the 63 positive cultures (18%), 44 dermatophytes (69.8%), 2 molds (3.2%), and 17 yeasts (27%) were isolated. The main dermatophyte species identified were Trichophyton rubrum (mostly from onychomycosis) and Microsporum canis (from tinea capitis and tinea corporis in children). Yeasts (Candida species) were isolated from nails, especially from women.

Evaluation of ID Fungi Plates Medium for Identification of Molds by MALDI Biotyper.

MALDI-TOF mass spectrometry (MS) identification of pathogenic filamentous fungi is often impaired by difficulties in harvesting hyphae embedded in the medium and long extraction protocols. The ID Fungi Plate (IDFP) is a novel culture method developed to address such difficulties and improve the identification of filamentous fungi by MALDI-TOF MS. We cultured 64 strains and 11 clinical samples on IDFP, Sabouraud agar-chloramphenicol (SAB), and ChromID Candida agar (CAN2). We then compared the three media for growth, ease of harvest, amount of material picked, and MALDI-TOF identification scores after either rapid direct transfer (DT) or a long ethanol-acetonitrile (EA) extraction protocol. Antifungal susceptibility testing and microscopic morphology after subculture on SAB and IDFP were also compared for ten molds. Growth rates and morphological aspects were similar for the three media. With IDFP, harvesting of fungal material for the extraction procedure was rapid and easy in 92.4% of cases, whereas it was tedious on SAB or CAN2 in 65.2% and 80.3% of cases, respectively. The proportion of scores above 1.7 (defined as acceptable identification) were comparable for both extraction protocols using IDFP (P = 0.256). Moreover, rates of acceptable identification after DT performed on IDFP (93.9%) were significantly higher than those obtained after EA extraction with SAB (69.7%) or CAN2 (71.2%) (P = <0.001 and P = 0.001, respectively). Morphological aspects and antifungal susceptibility testing were similar between IDFP and SAB. IDFP is a culture plate that facilitates and improves the identification of filamentous fungi, allowing accurate routine identification of molds with MALDI-TOF-MS using a rapid-extraction protocol.

Serodiagnosis of Extraintestinal Amebiasis: Retrospective Evaluation of the Diagnostic Performance of the Bordier® ELISA Kit.

Soluble antigens from an axenic culture of Entamoeba histolytica were used to develop a commercial ELISA kit to quantify anti-E. histolytica antibodies in sera of patients with extraintestinal amebiasis in non-endemic settings. The diagnostic specificity and sensitivity of the test were assessed retrospectively using 131 human serum samples with amoebic serologic status available. They were selected according to their results in immunofluorescence (IFAT) and were separated in 2 sample categories: 64 sera with positive results by IFAT and 67 with negative results by IFAT. The sensitivity and specificity of the ELISA kit were assessed at 95.0% and 94.0% compared to the IFAT. The test can be useful to exclude a potential diagnosis of amebiasis and could be used as a screening method since ELISA is an automated technique.

Direct Molecular Diagnosis of Aspergillosis and CYP51A Profiling from Respiratory Samples of French Patients.

BACKGROUND: Microbiological diagnosis of aspergillosis and triazole resistance is limited by poor culture yield. To better estimate this shortcoming, we compared culture and molecular detection of A. fumigatus in respiratory samples from French patients at risk for aspergillosis. METHODS: A total of 97 respiratory samples including bronchoalveolar lavages (BAL), bronchial aspirates (BA), tracheal aspirates, sputa, pleural fluids, and lung biopsy were collected from 33 patients having invasive aspergillosis (n = 12), chronic pulmonary aspergillosis (n = 3), allergic bronchopulmonary aspergillosis (n = 7), or colonization (n = 11) and 28 controls. Each specimen was evaluated by culture, pan-Aspergillus qPCR, and CYP51A PCR and sequencing. RESULTS: One A. flavus and 19 A. fumigatus with one multiazole resistant strain (5.3%) were cultured from 20 samples. Culture positivity was 62.5, 75, 42.9, and 15.8% in ABPA, CPA, IA, and colonized patients, respectively. Aspergillus detection rate was significantly higher by pan-Aspergillus qPCR than by culture in IA (90.5 vs. 42.9%; P < 0.05) and colonization group (73.7 vs. 15.8%; P < 0.05). The CYP51A PCR found one TR34/L98H along with 5 novel cyp51A mutations (4 non-synonymous and 1 promoter mutations), yet no association can be established currently between these novel mutations and azole resistance. The analysis of 11 matched pairs of BA and BAL samples found that 9/11 BA carried greater fungal load than BAL and CYP51A detection was more sensitive in BA than in BAL. CONCLUSION: Direct molecular detection of Aspergillus spp. and azole resistance markers are useful adjunct tools for comprehensive aspergillosis diagnosis. The observed superior diagnostic value of BAs to BAL fluids warrants more in-depth study.

Characteristic and clinical relevance of Candida mannan test in the diagnosis of probable invasive candidiasis.

The gold standard laboratory tests used to diagnose invasive Candida infection (ICI) are based on the in vitro culture of blood or samples from other sterile sites. However, these tests have limited sensitivity (Se) and are generally not diagnostic until late in the infectious process. The Serion Candida mannan kit was evaluated for the diagnosis of ICI at Grenoble University Hospital (France) between 2007 and 2011. The results were then compared with worldwide data published between 1997 and 2011. This retrospective study was based on follow-up from the investigation of 162 patients of whom 91 had proven ICI; 13 had Candida colonization index (CCI) scores ≥0.42, positive mannan tests, with nonconcomitant infections; and 58 had no evidence of Candida infection. Candida albicans, C. glabrata, C. tropicalis, and C. parapsilosis were the etiologic agents in 104 patients. For patients with or without ICI, the 12-week mortality rates were 35/104 (33.7%) and 6/58 (10.3%), respectively. The mannan diagnostic specificity was 51% and Se was 77%. However, in the meta-analysis (n = 1,536), values were 86% and 62%, respectively. Positive mannan test results may appear early (median 6 days) in the development of candidemia and have moderate diagnostic value for ICI, with a negative predictive value of 83%. In patients at risk of ICI with negative candidemia, the combination of Candida mannan test data with a CCI score ≥0.42 may improve the diagnosis of probable ICI.