bInvasive fungal infections have a high rate of morbidity and mortality, and accurate identification is necessary to guide appropriate antifungal therapy. With the increasing incidence of invasive disease attributed to filamentous fungi, rapid and accurate species-level identification of these pathogens is necessary. Traditional methods for identification of filamentous fungi can be slow and may lack resolution. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has emerged as a rapid and accurate method for identification of bacteria and yeasts, but a paucity of data exists on the performance characteristics of this method for identification of filamentous fungi. The objective of our study was to evaluate the accuracy of the Vitek MS for mold identification. A total of 319 mold isolates representing 43 genera recovered from clinical specimens were evaluated. Of these isolates, 213 (66.8%) were correctly identified using the Vitek MS Knowledge Base, version 3.0 database. When a modified SARAMIS (Spectral Archive and Microbial Identification System) database was used to augment the version 3.0 Knowledge Base, 245 (76.8%) isolates were correctly identified. Unidentified isolates were subcultured for repeat testing; 71/ 319 (22.3%) remained unidentified. Of the unidentified isolates, 69 were not in the database. Only 3 (0.9%) isolates were misidentified by MALDI-TOF MS (including Aspergillus amoenus [n ‫؍‬ 2] and Aspergillus calidoustus [n ‫؍‬ 1]) although 10 (3.1%) of the original phenotypic identifications were not correct. In addition, this methodology was able to accurately identify 133/144 (93.6%) Aspergillus sp. isolates to the species level. MALDI-TOF MS has the potential to expedite mold identification, and misidentifications are rare. Filamentous fungi are ubiquitous environmental microorganisms that have become increasingly important pathogens, especially in immunocompromised patients. Invasive fungal diseases have a high rate of morbidity and mortality, and accurate identification is necessary to guide appropriate antifungal therapy. Traditionally, the identification of filamentous fungi has required the use of different phenotypic methods in conjunction with macro-and microscopic assessment of the organism (1). This process requires highly trained mycologists, and, in some cases, turnaround time may be prolonged due to a requirement for extended incubation periods, potentially delaying appropriate therapy. Molecular methods, which can provide accurate identification to the species level, can be expensive, require specialized equipment or expertise, and are not commonly available in clinical laboratories.Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been utilized in the clinical microbiology laboratory for rapid and accurate identification of bacteria, mycobacteria, and yeasts (2-9). For filamentous fungi, databases have been limited, and unlike bacteria, filamentous fungi require additional processing steps to dis...

The accuracy of Vitek MS mass spectrometric identifications was assessed for 206 clinically significant isolates of aerobic Grampositive bacilli representing 20 genera and 38 species. The Vitek MS identifications were correct for 85% of the isolates (56.3% to the species level, 28.6% limited to the genus level), with misidentifications occurring for 7.3% of the isolates. I dentification of aerobic, Gram-positive bacilli (GPB) to the species level is challenging. Biochemical methods are slow and labor-intensive and may not provide reliable results. Molecular sequencing techniques have become the gold standard for identification of GPB (1-3) but are too expensive for routine use by the clinical microbiology laboratory. As a consequence, GPB identifications are often limited to the genus level or descriptive results (e.g., diphtheroid).Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a new technology offering accurate, fast, and affordable identification for bacteria and yeasts (4-7). Mass spectrometry results are graphed as peaks based on the mass/charge ratio of microbial proteins that have been ionized from intact cells obtained from pure culture. Identification is achieved by comparison of the mass spectral profile to a reference database.The purpose of this study was to evaluate the accuracy of MALDI-TOF MS identifications generated by the Vitek MS system (v2.0; bioMérieux, Durham, NC) for aerobic GPB isolates commonly encountered in the clinical microbiology laboratory. The Vitek MS results were compared to identifications previously reported that were based on conventional biochemical or molecular methods. Sequencing of 16S rRNA or rpoB genes was performed to arbitrate discordant results. Although the Vitek MS system recently received FDA 510(k) de novo clearance, only a few of the species analyzed in this current study were included in the FDA clinical trials and data submission.A total of 206 GPB isolates recovered from specimens submitted for culture from 31 December 2007 to 21 August 2012 were selected from the frozen stock database of the Cleveland Clinic Clinical Microbiology Laboratory for inclusion in the study. Duplicate isolates of the same species from a single patient were excluded. Approval was received by the institutional review board prior to initiation of the study. These clinical isolates had been previously identified using biochemical testing or molecular methods (sequencing of 16S rRNA or rpoB genes). The frozen isolates were plated on 5% sheep blood agar and incubated overnight at 35°C in 5% CO 2 . Isolates were subcultured a second time before Vitek MS testing was performed. The manufacturer's instructions were followed for Vitek MS testing.A thin film of fresh colony growth was applied directly to the target slide. Each spot was covered with 1 l of matrix solution (␣-cyano-4-hydroxycinnamic acid; bioMérieux), allowed to dry, and analyzed on the Vitek MS instrument. If two attempts at direct colony testing failed to provide an acceptable si...

eWe present the first case of candidemia due to Candida quercitrusa in a pediatric patient. The identification of the isolate was protracted and ultimately dependent upon sequence analysis of the internal transcribed spacer region. To further define the antifungal susceptibility characteristics of this species, we performed antifungal susceptibility testing of clinical and type strains. In light of the antifungal susceptibility testing results, we caution against the use of fluconazole for treating C. quercitrusa infections. CASE REPORT The patient was a 6-year-old male with a history of malignant sacrococcygeal teratoma requiring sacrectomy and radiation therapy during infancy. He had subsequently developed neurogenic bladder, requiring a Mitrofanoff appendicovesicostomy, and neurogenic bowel, requiring a diverting ileostomy. He had gastroparesis with chronic emesis and was therefore dependent on gastrojejunal feeds and total parenteral nutrition (TPN). His medical history was notable for multiple infectious complications involving his central venous line (CVL), and he had received multiple courses of micafungin, voriconazole, and fluconazole separated in time from 2009 onward. Five months prior to admission, he had been diagnosed with a Mycobacterium abscessus tunnel infection of his CVL with an associated chest wall abscess. The abscess had been incised and drained, and the patient had been placed on chronic azithromycin therapy. During the same hospitalization, he was found to have Candida glabrata candidemia (the isolate was identified in house), which was treated with liposomal amphotericin B at a dosage of 3 mg/kg of body weight every 24 h initially, followed by 4 mg/kg micafungin every 24 h for a total of 14 days. Two months prior to admission, he was hospitalized with Candida famata candidemia (the isolate was identified at an outside institution), and he received 2 mg/kg micafungin every 24 h for 6 days, followed by 9 mg/kg voriconazole every 12 h for 10 days based on antifungal susceptibility testing data. His contaminated CVL was removed and a new peripherally inserted central catheter (PICC) was inserted 6 weeks prior to admission. He was then placed on oral nystatin (300,000 units twice a day) for antifungal prophylaxis.The patient presented to our facility with low-grade fevers that had persisted for approximately 1 month. His laboratory values were notable for thrombocytopenia (platelets, 92,000/l) and a mildly elevated level of C-reactive protein (3.9 mg/dl). Three independent aerobic blood cultures (BacT/Alert Pediatric FAN; bioMérieux, Marcy l'Etoile, France) obtained from his PICC line on hospital days 1, 2, and 5 grew yeasts on hospital days 4, 5, and 10, respectively. The yeast isolates were prepared for identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) on the Bruker Biotyper platform (Bruker Daltonics, Bremen, Germany) using an extraction method (1). When queried against the database (Biotyper version 3.1.66 [5,627 entries]), the ...