ABSTRACT
SESSION TITLE: Respiratory Infections: What have We Learned About COVID-19 and New Trial Data for Management of Aspergilloma SESSION TYPE: Original Investigations PRESENTED ON: October 18-21, 2020 PURPOSE: To describe clinical characteristics of U.S. patients with pulmonary Mycobacterium avium complex (PMAC) whose sputum cultures were identified by gene sequence as M. chimaera. To highlight importance of MAC species identification (ID) following clinically focused assessment of PMAC patients. METHODS: From 2013-2019, sputum samples from 89 patients seen at the University of Texas Health Science Center at Tyler (UTHSCT) underwent processing for smear and culture of mycobacteria with species ID using partial 16S rRNA gene and ITS sequencing at first visit and at a minimum every 6 months thereafter. Clinical information was extracted from medical records. Microbiological significance of M. chimaera was assessed based on semi-quantitative colony count, smear positivity, and presence of the organism in broth only, broth and solid culture, and number of positive cultures. Clinical significance was based on symptoms, lung function and radiographic features. PMAC was defined according to 2007 ATS/IDSA criteria. RESULTS: M. chimaera was grown in 146 cultures from 89 patients. The mean patient age was 70.4 +/-10.3 years and 69% were women. The mean FEV1 percent predicted was 64% (SD, 24%). Only 4 patients were current tobacco smokers, 39% (35/89) patients had a history of >10 pack years. M. chimaera was associated with cavitary disease in 22% (20/89) patients and nodular bronchiectasis disease in 78% (69/89) of patients. Of the patients with nodular bronchiectasis, 35% (24/69) had multiple samples yielding M. chimaera. A single positive culture of the species occurred in 63% (56/89) of patients. Only 14% (20/146) cultures of M. chimaera had positive AFB smears and only 65/146 (45%) of total cultures were positive on solid media while 79/146 (54%) were positive in broth only. Isolates that were AFB smear negative and associated with a single positive culture grown only in broth did not meet ATS/IDSA guidelines for PMAC disease and therefore did not require therapy. CONCLUSIONS: This is the first large study of pulmonary M. chimaera in the U.S. PMAC infection with M. chimaera manifests as a variable clinical picture in patients. Identification of MAC species level ID is essential to understand the significance and pathogenicity of M. chimaera. CLINICAL IMPLICATIONS: ATS/IDSA criteria for PMAC disease was written in the context of M. avium and M. intracellulare infection. These criteria may not be applicable for other MAC species. ID of MAC isolates to the species level is an integral step in appropriate management of patients with sputum that grows M. chimaera. DISCLOSURES: Laboratory Research Grant relationship with Insmed Please note: >$100000 Added 06/01/2020 by Barbara Brown-Elliott, source=Admin input, value=Grant/Research Support Advisory Committee Member relationship with Insmed Inc Please note: $1001 - $5000 Added 06/12/2020 by David Griffith, source=Web Response, value=Consulting fee Consultant relationship with Insmed Inc. Please note: >$100000 Added 06/12/2020 by David Griffith, source=Web Response, value=Grant/Research Support Consultant relationship with Insmed Inc. Please note: $5001 - $20000 Added 06/12/2020 by David Griffith, source=Web Response, value=Consulting fee No relevant relationships by ELENA IAKHIAEVA, source=Web Response No relevant relationships by Pamela McShane, source=Web Response Consultant relationship with INSMED Please note: $1-$1000 by Julie Philley, source=Web Response, value=Honoraria Advisory Committee Member relationship with Janseen Please note: $1-$1000 by Julie Philley, source=Web Response, value=Honoraria Advisory Committee Member relationship with INSMED Please note: $1001 - $5000 by Julie Philley, source=Web Response, value=Consulting fee No relevant relationships by Carly Sigler, source=Web Response No relevant relationships by Sruthi Vasireddy, source=Web Response grant for labor tory study of arikace relationship with Insmed Please note: >$100000 Added 06/02/2020 by Richard Wallace, source=Web Response, value=grant to support lab work