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Protein profile typing--a new method of typing Morganella morganii strains
1Department of Medical Microbiology, Dundee University Medical School, Ninewells Hospital.
Abstract:
A new, simple and stable method for typing Morganella morganii strains is described. The 150 strains examined, principally from faeces, contained haemolytic and non-haemolytic representatives of diverse O serogroup, bacteriocin type and biotype. Among the biotypes were some trehalose-fermenting, tetracycline-resistant strains and some non-motile, tetracycline-sensitive, glycerol fermenters. After analysis of cell lysates by sodium dodecyl sulphate-discontinuous polyacrylamide gel electrophoresis, strains could be differentiated into 21 types on the basis of outer membrane proteins (OMP) of 35-40 Kda. The OMP profile was not altered by culture on various common media and was unrelated to either O antigen or morganocin p-type. The finest strain recognition in M. morganii can be achieved by application of all three distinct typing methods.
Insights
A new method using outer membrane proteins (OMP) effectively types Morganella morganii strains. Combining OMP analysis with existing methods offers the best strain recognition for this bacterium.
Area of Science:
- Microbiology
- Bacteriology
- Molecular typing
Background:
- Morganella morganii is a Gram-negative bacterium found in various environments.
- Accurate strain typing is crucial for epidemiological studies and infection control.
- Existing typing methods for M. morganii have limitations in resolution and stability.
Purpose of the Study:
- To develop and evaluate a simple, stable, and effective method for typing Morganella morganii strains.
- To assess the utility of outer membrane protein (OMP) profiles for strain differentiation.
- To compare the new OMP typing method with existing serotyping, bacteriocin typing, and biotyping.
Main Methods:
- Analysis of 150 Morganella morganii strains from fecal samples.
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of cell lysates to analyze outer membrane proteins (OMPs).
- Differentiation of strains based on OMP profiles (35-40 KDa) and comparison with O serogroup, bacteriocin type, and biotype.
Main Results:
- Outer membrane protein (OMP) profiles differentiated the 150 strains into 21 distinct types.
- The OMP profiles remained stable across different culture media.
- OMP profiles were independent of O antigen and morganocin p-type, indicating a distinct discriminatory marker.
- Biotype variations included trehalose-fermenting, tetracycline-resistant strains and non-motile, glycerol-fermenting, tetracycline-sensitive strains.
Conclusions:
- Outer membrane protein (OMP) electrophoresis provides a simple, stable, and effective method for typing Morganella morganii.
- Combining OMP typing with O serogroup, bacteriocin type, and biotype offers the highest discriminatory power for M. morganii strain recognition.
- This multi-faceted approach enhances the ability to track and manage M. morganii in clinical and epidemiological settings.