Study of environmental Mycobacterium abscessus isolates and outbreaks in experimental murine infection

• Grant number: 07/03185-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2007
• End date: February 28, 2009
• Field of knowledge: Biological Sciences - Microbiology
• Principal Investigator: Sylvia Luisa Pincherle Cardoso Leão
• Grantee: Janaina Mitie Serikawa
• Host Institution: Departamento de Microbiologia, Imunologia e Parasitologia. Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Non-tuberculous mycobacteria (NTM) are emerging pathogens which are able to cause infections in immunocompromised and immunocompetent patients. Rapidly Growing Mycobacteria (RGM) have been reported as causative agents of infection outbreaks in humans with increasing frequency. The anatomo-pathological substrate of micobacterial infections is the granuloma, a chronic inflammatory lesion. This lesion is constituted of many cell types, including macrophages and macrophage-derived cells, such as giant multinuclear and epithelioid cells (CEs). Our group, interested in better understanding CEs function, developed the unique described model for the in vitro generation of cells (CEs-like) presenting morphological and functional characteristics similar to those described for CEs found in granulomas. Using this model, we demonstrated that CEs-like harbor and arrest Mycobacterium avium multiplication in vitro, while peritoneal resident macrophages do not control the infection. In the present project, Mycobacterium abscessus isolates from outbreaks and environmental sources will be compared with respect to infection in the mouse model. Microbiological (colony forming units in lungs and spleen) and hystopathological characteristics will be compared after infection with strains from different sources. The evolution of the ex vivo infection in peritoneal macrophages and CEs-like will also be evaluated.