Mycobacteria clumping increase their capacity to damage macrophages
Brambilla, Cecilia (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Llorens Fons, Marta (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Julián Gómez, Esther (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Noguera-Ortega, Estela (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Tomàs Martínez, Cristina (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Pérez-Trujillo, Míriam (Universitat Autònoma de Barcelona. Departament de Química)
Byrd, Thomas F. (The University of New Mexico School of Medicine)
Alcaide, Fernando (Universitat de Barcelona)
Luquín Fernández, Marina (Marina) (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)

Date:	2016
Abstract:	The rough morphotypes of non-tuberculous mycobacteria have been associated with the most severe illnesses in humans. This idea is consistent with the fact that Mycobacterium tuberculosis presents a stable rough morphotype. Unlike smooth morphotypes, the bacilli of rough morphotypes grow close together, leaving no spaces among them and forming large aggregates (clumps). Currently, the initial interaction of macrophages with clumps remains unclear. Thus, we infected J774 macrophages with bacterial suspensions of rough morphotypes of M. abscessus containing clumps and suspensions of smooth morphotypes, primarily containing isolated bacilli. Using confocal laser scanning microscopy and electron microscopy, we observed clumps of at least five rough-morphotype bacilli inside the phagocytic vesicles of macrophages at 3 h post-infection. These clumps grew within the phagocytic vesicles, killing 100% of the macrophages at 72 h post-infection, whereas the proliferation of macrophages infected with smooth morphotypes remained unaltered at 96 h post-infection. Thus, macrophages phagocytose large clumps, exceeding the bactericidal capacities of these cells. Furthermore, proinflammatory cytokines and granuloma-like structures were only produced by macrophages infected with rough morphotypes. Thus, the present study provides a foundation for further studies that consider mycobacterial clumps as virulence factors.
Grants:	Instituto de Salud Carlos III PI12/00025 Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-132
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Mycobacterium abscessus ; Virulence factors ; Infection of macrophages ; Clumps ; Cords ; Rough morphotypes ; Smooth morphotypes
Published in:	Frontiers in microbiology, Vol. 7 (October 2016) , art. 1562, ISSN 1664-302X

DOI: 10.3389/fmicb.2016.01562
PMID: 27757105

12 p, 1.1 MB

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