Microbiological profile of slow-growing non-tuberculous mycobacteria species other than Mycobacterium avium complex.

Mariana Fernández-Pittol ^1,2,3 Sara Batista ^2,4 Sofía Narváez ⁵ Angely Román ¹ Lorena San Nicolas ¹ Diego Martínez ¹ Laura Oliver ⁶ Olga González-Moreno ⁶ José Antonio Martínez ^7,8 Felipe García ⁷ Rosanel Amaro-Rodríguez ⁹ Nestor Soler ⁹ Amadeu Gené ¹⁰ Araceli González-Cuevas ¹⁰ Griselda Tudó ^1,2,3 Julian Gonzalez-Martin ^1,2,3,8*

• ¹ Hospital clinic of Barcelona, Servei de Microbiologia, CDB, Barcelona, Balearic Islands, Spain
• ² Departament de Fonaments Clínics, Facultat de Medicina i Ciències de la Salut. Universitat de Barcelona, Barcelona, Barcelona, Barcelona, Spain
• ³ ISGLOBAL, Institute for Global Health, Barcelona, Balearic Islands, Spain
• ⁴ Fundació de Recerca Clínic Barcelona -Institut d’Investigacions Biomèdiques August Pi i Sunyer (FRCB-IDIBAPS), Barcelona, Spain, Barcelona, Spain
• ⁵ Catlab. Centre Analítiques Terrassa AIE, Servei de Microbiología/ Vallés Occidental Parc Logístic de Salut Vial Sant Jordi, Viladecavalls, Barcelona, Spain
• ⁶ SYNLAB Diagnósticos Globales. Departamento de Microbiología y Parasitología., Barcelona, Spain
• ⁷ Servei de Malalties Infeccioses, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
• ⁸ CIBER of Infectious Diseases (CIBERINFEC), Instituto de Salud Carlos III, 28029, Madrid, Spain
• ⁹ Department of Pneumology, Hospital Clinic of Barcelona, Barcelona, Balearic Islands, Spain
• ¹⁰ Laboratori, Hospital Sant Joan De Deu, Barcelona, Spain

Mycobaterium avium complex (MAC) and Mycobacterium abscessus complex are the primary agents of non-tuberculous mycobacteria infection. However, other species within the slow-growing group can also be potentially pathogenic, although information on these species is limited. Objectives: we conducted a prospective analysis of slow-growing species other than MAC, aimed at the identification and microbiological profiles of clinical samples from a tertiary hospital. The Microbiology Department of the Hospital Clinic of Barcelona, the Microbiology Laboratory of SYNLAB Laboratories, and the Microbiology Laboratory of Hospital Sant Joan de Deu participated in the study. Methods: species identification was conducted by MALDI-TOF MS and/or 16S rRNA and rpoB gene sequencing. Drug susceptibility tests (DST) were performed using the microdilution method. The results of the susceptibility profiles were compared with treatment guidelines, or the most recent literature related to each species. Results: Twenty-five different species belonging to the slow-growing group were identified. The most frequently observed were M. xenopi, M. kansasii, M. gordonae and M. marinum. In this series, M. lentiflavum presented the highest susceptibility profile, while M. simiae demonstrated the highest level of resistance. Clarithromycin, rifabutin, and amikacin demonstrated high levels of effectiveness across all species. The species most associated with infection, presented a high correlation with the clinical treatment guidelines. Conclusions: A specific susceptibility profile was observed among all the species. The in vitro profiles of the most frequent species correlated with the clinical treatment guidelines, reinforcing the supporting role of DST in the design of individualised treatment for each patient.