AUTHOR=Belardinelli Juan M. , Li Wei , Avanzi Charlotte , Angala Shiva K. , Lian Elena , Wiersma Crystal J. , Palčeková Zuzana , Martin Kevin H. , Angala Bhanupriya , de Moura Vinicius C. N. , Kerns Callan , Jones Victoria , Gonzalez-Juarrero Mercedes , Davidson Rebecca M. , Nick Jerry A. , Borlee Bradley R. , Jackson Mary TITLE=Unique Features of Mycobacterium abscessus Biofilms Formed in Synthetic Cystic Fibrosis Medium JOURNAL=Frontiers in Microbiology VOLUME=12 YEAR=2021 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.743126 DOI=10.3389/fmicb.2021.743126 ISSN=1664-302X ABSTRACT=

Characterizing Mycobacterium abscessus complex (MABSC) biofilms under host-relevant conditions is essential to the design of informed therapeutic strategies targeted to this persistent, drug-tolerant, population of extracellular bacilli. Using synthetic cystic fibrosis medium (SCFM) which we previously reported to closely mimic the conditions encountered by MABSC in actual cystic fibrosis (CF) sputum and a new model of biofilm formation, we show that MABSC biofilms formed under these conditions are substantially different from previously reported biofilms grown in standard laboratory media in terms of their composition, gene expression profile and stress response. Extracellular DNA (eDNA), mannose-and glucose-containing glycans and phospholipids, rather than proteins and mycolic acids, were revealed as key extracellular matrix (ECM) constituents holding clusters of bacilli together. None of the environmental cues previously reported to impact biofilm development had any significant effect on SCFM-grown biofilms, most likely reflecting the fact that SCFM is a nutrient-rich environment in which MABSC finds a variety of ways of coping with stresses. Finally, molecular determinants were identified that may represent attractive new targets for the development of adjunct therapeutics targeting MABSC biofilms in persons with CF.