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Investigation of the haemolytic activity of Proteus mirabilis strains
Abstract:
Young broth cultures of all P. mirabilis strains tested exhibited haemolytic activity. This activity seemed to be strongly cell-associated as only a very small fraction of this activity was found in the cell-free supernatant. The haemolysin was only produced by actively growing cells. Inhibition studies with trypsin and chloramphenicol suggested that the haemolysin is of protein nature. Lecithin and serum of several species had an inhibitory effect on the haemolysin. Besides erythrocytes of various species also VERO cells were affected by the haemolysin. A correlation was found between the haemolytic activity of a strain and its virulence in an experimental mouse model.
Insights
Proteus mirabilis produces a cell-associated hemolysin during active growth. This protein hemolysin affects various cells and correlates with virulence in mice.
Area of Science:
- Microbiology
- Bacteriology
- Molecular Biology
Background:
- Proteus mirabilis is an opportunistic pathogen.
- Hemolytic activity is a virulence factor in many bacteria.
- The nature and function of P. mirabilis hemolysin require further investigation.
Purpose of the Study:
- To characterize the hemolysin produced by P. mirabilis.
- To investigate the relationship between hemolysin production and bacterial virulence.
Main Methods:
- Assessing hemolytic activity in broth cultures and cell-free supernatants.
- Investigating the effect of growth phase on hemolysin production.
- Using enzyme inhibitors (trypsin, chloramphenicol) to determine protein nature.
- Testing inhibitory effects of lecithin and serum.
- Evaluating hemolysin's effect on erythrocytes and VERO cells.
- Correlating hemolytic activity with mouse model virulence.
Main Results:
- All tested P. mirabilis strains exhibited cell-associated hemolytic activity.
- Hemolysin production was restricted to actively growing cells.
- Inhibition studies indicated the hemolysin is proteinaceous.
- Lecithin and serum inhibited hemolysin activity.
- Hemolysin affected erythrocytes and VERO cells.
- A positive correlation was observed between hemolytic activity and mouse virulence.
Conclusions:
- P. mirabilis produces a cell-associated, proteinaceous hemolysin.
- This hemolysin is produced during active growth.
- The hemolysin impacts host cells and is linked to P. mirabilis virulence.