Historically, the detection and identification of bacteria, mycobacteria, yeasts, and molds have relied primarily on their morphologic and phenotypic properties. This approach is imprecise and slow for many clinically significant microbes. We have explored alternative methods, such as targeted sequencing and mass spectrometry, for the detection and identification of selected organisms. Studies in the current fiscal year have focused on alternative identification methods, specifically MALDI-TOF (matrix-assisted laser desorption-ionization time of flight mass spectrometry) for the identification of Nocardia, mycobacteria, and molds and rapid genomic assays for identification, typing and detection of antibiotic resistance in M. abscessus group. MALDI-TOF MS provides a reproducible spectral pattern based on the mass/charge (m/z) ratio of ionized proteins. Preparation of samples is rapid and inexpensive. Well-characterized reference strains of mycobacteria, Nocardia and molds allowed us to build a NIH database that was then challenged with clinical isolates. Following a demonstration of excellent performance, MALDI-TOF MS has become the method of choice of the NIH Microbiology Service for identification of both rapid and slowly growing mycobacteria as well as filamentous molds. This approach has been recently validated for the identification of Nocardia at the NIH and more recently also at two other academic centers. A multi center evaluations of the performance of the NIH mold database is ongoing. Finally, we are exploring the use of proteomics and in particular Maldi-Tof MS for direct detection of microbial antigens in clinical samples and our project was granted a Bench to Bedside (BtB) award. Our findings support the validity of this approach for detection of circulating antigens of Mycobacterium tuberculosis and Mycobacterium avium complex and is being currently evaluated for other species of mycobacteria.

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Conville, Patricia S; Brown-Elliott, Barbara A; Smith, Terry et al. (2018) The Complexities of Nocardia Taxonomy and Identification. J Clin Microbiol 56:
Luethy, Paul M; Zelazny, Adrian M (2018) Rapid one-step extraction method for the identification of molds using MALDI-TOF MS. Diagn Microbiol Infect Dis 91:130-135
Zhang, Wei; Shu, Qingbo; Zhao, Zhen et al. (2018) Antigen 85B peptidomic analysis allows species-specific mycobacterial identification. Clin Proteomics 15:1
Natarajan, Mukil; Swierzbinski, Matthew J; Maxwell, Sandra et al. (2017) Pulmonary Histoplasma Infection After Allogeneic Hematopoietic Stem Cell Transplantation: Case Report and Review of the Literature. Open Forum Infect Dis 4:ofx041
Hesse, Shayla E; Luethy, Paul M; Beigel, John H et al. (2017) Penicillium citrinum: Opportunistic pathogen or idle bystander? A case analysis with demonstration of galactomannan cross-reactivity. Med Mycol Case Rep 17:8-10
Haidar, Ghady; Zerbe, Christa S; Cheng, Michelle et al. (2017) Phellinus species: An emerging cause of refractory fungal infections in patients with X-linked chronic granulomatous disease. Mycoses 60:155-160
Liu, Chang; Zhao, Zhen; Fan, Jia et al. (2017) Quantification of circulating Mycobacterium tuberculosis antigen peptides allows rapid diagnosis of active disease and treatment monitoring. Proc Natl Acad Sci U S A 114:3969-3974
Falcone, E Liana; Petts, Jennifer R; Fasano, Mary Beth et al. (2016) Methylotroph Infections and Chronic Granulomatous Disease. Emerg Infect Dis 22:404-9
Blosser, Sara J; Drake, Steven K; Andrasko, Jennifer L et al. (2016) Multicenter Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Study for Identification of Clinically Relevant Nocardia spp. J Clin Microbiol 54:1251-8
Jitmuang, Anupop; Panackal, Anil A; Williamson, Peter R et al. (2016) Performance of the Cryptococcal Antigen Lateral Flow Assay in Non-HIV-Related Cryptococcosis. J Clin Microbiol 54:460-3

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