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Extracellular hemolytic activity in rapidly growing mycobacteria
1Division of Clinical Microbiology, School of Medical Technology, University of Occupational and Environmental Health, Kitakyushu, Japan.
Canadian Journal of Microbiology
|April 1, 1994
Summary
Rapidly growing mycobacteria, including Mycobacterium fortuitum and Mycobacterium chelonae, produce an extracellular hemolytic substance. This substance may contribute to disease pathogenesis and exhibits stability and specific characteristics.
Area of Science:
- Microbiology
- Pathogenesis research
- Bacterial virulence factors
Background:
- Virulence factors of rapidly growing mycobacteria are not well understood.
- Mycobacterium fortuitum and Mycobacterium chelonae are clinically significant rapidly growing mycobacteria.
Purpose of the Study:
- To investigate the production of hemolysin by clinical isolates of rapidly growing mycobacteria.
- To assess the potential role of hemolysin in the pathogenesis of diseases caused by these bacteria.
Main Methods:
- Evaluation of 42 clinical isolates of Mycobacterium fortuitum and Mycobacterium chelonae, plus 4 reference strains of Mycobacterium smegmatis.
- Testing for extracellular hemolytic activity, stability after heating and proteinase treatment, and molecular weight of the active substance.
- Monitoring hemolysin accumulation during bacterial growth phases and in vitro hemolysis kinetics.
Main Results:
- All tested mycobacterial strains exhibited extracellular hemolytic activity.
- The hemolytic substance was stable to heat and proteinase treatment, with a molecular weight under 10,000.
- Hemolytic activity peaked during the late exponential to mid-stationary growth phase and required 10 hours for maximal in vitro effect, showing some species-specific red blood cell preference.
Conclusions:
- Rapidly growing mycobacteria produce a stable, low-molecular-weight extracellular hemolysin.
- This hemolysin is a potential virulence factor contributing to mycobacterial pathogenesis.
- Further research into this hemolytic substance could inform therapeutic strategies against infections caused by these organisms.