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Typing of Proteus mirabilis from clinical sources by computerized analysis of electrophoretic protein patterns
1National Collection of Type Cultures, Central Public Health Laboratory, London, UK.
Abstract:
Seventy-five strains of Proteus mirabilis (mainly of human origin) were characterized by one-dimensional SDS-PAGE of cellular proteins. The strains came from various countries; 24 were from urine, 17 from faeces (including one from a dog and one from a monkey), 12 from the respiratory tract (including nine from sputum), four from a cerebral abscess, 12 from miscellaneous sources and six from unknown sources. The protein patterns, which contained 45 to 50 discrete bands, were highly reproducible. The patterns of the 75 P. mirabilis cultures plus those of the type strains of six Proteus and Providencia species were used as the basis for two numerical analyses. In the first, which included all the protein bands, the P. mirabilis cultures formed nine clusters at the 85% S level. In the second analysis, in which the principal protein bands (in the 34.0-44.6 kDa range) were excluded, 74 of the 75 cultures of P. mirabilis formed a single cluster at the 77% S level distinct from the six Proteus and Providencia reference strains. The P. mirabilis strain which failed to cluster with the others had a background band pattern typical of the species in the lower molecular weight region but appeared to be less typical in the heavier bands. It is concluded that high resolution PAGE combined with computerized analysis of protein patterns provides the basis for typing clinical strains of P. mirabilis. Reference strains of each of the nine PAGE types identified are available from NCTC for inclusion in future studies.
Insights
This study used protein analysis to type Proteus mirabilis strains from various sources. High-resolution SDS-PAGE and numerical analysis effectively differentiated clinical Proteus mirabilis isolates.
Area of Science:
- Microbiology
- Biochemistry
- Bioinformatics
Background:
- Proteus mirabilis is a significant human pathogen.
- Accurate typing of bacterial strains is crucial for epidemiological studies and clinical diagnostics.
- Previous typing methods for P. mirabilis have limitations.
Purpose of the Study:
- To evaluate the utility of one-dimensional SDS-PAGE of cellular proteins for typing clinical strains of Proteus mirabilis.
- To develop a robust and reproducible method for differentiating P. mirabilis isolates.
Main Methods:
- Seventy-five clinical isolates of Proteus mirabilis were characterized using one-dimensional SDS-PAGE.
- Protein patterns were analyzed using two numerical methods, including analysis of all bands and exclusion of principal bands.
- Comparative analysis was performed with type strains of related Proteus and Providencia species.
Main Results:
- SDS-PAGE protein patterns were highly reproducible, displaying 45-50 discrete bands.
- Numerical analysis of all protein bands resulted in nine distinct clusters of P. mirabilis.
- Excluding principal protein bands (34.0-44.6 kDa) allowed 74 of 75 strains to form a single, distinct cluster.
Conclusions:
- High-resolution SDS-PAGE combined with computerized numerical analysis is a reliable method for typing clinical strains of Proteus mirabilis.
- This technique provides a basis for differentiating P. mirabilis isolates based on their protein profiles.
- Reference strains representing identified PAGE types are available for future research.