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Characteristics of spontaneously agglutinating Proteus mirabilis strains from bacteriuric patients
D Krajewska-Pietrasik1, P Larsson, K Zych
1Institute of Microbiology, University of Lodz, Poland.
Abstract:
Out of 210 Proteus mirabilis isolates from bacteriuric patients a total of eight spontaneously agglutinating strains were found. SDS-PAGE analysis of their lipopolysaccharides (LPS), the separation of polysaccharide fractions (PS) by gel filtration, and chemical characterization of PSs were performed. Out of the eight strains one S form and one mutant classified as Rc were detected. The remaining six strains were recognized as Ra and intermediate forms. When tested in a hematogenous infection model in mice, the P. mirabilis Rc mutant survived in kidneys for at least two weeks, while the Re mutant used as control was eliminated within 20 h after the challenge. These data indicated that strains of P. mirabilis may be pathogenic even if they express very incomplete LPS.
Insights
Certain Proteus mirabilis strains with incomplete lipopolysaccharides (LPS) can still cause infections. This study found that even altered LPS structures in P. mirabilis can lead to kidney survival in a mouse model, indicating potential pathogenicity.
Area of Science:
- Microbiology
- Immunology
- Pathogenesis
Background:
- Proteus mirabilis is a common cause of urinary tract infections.
- Lipopolysaccharides (LPS) are key components of Gram-negative bacteria outer membranes, influencing pathogenicity.
- The structure of LPS can vary, affecting bacterial-host interactions.
Purpose of the Study:
- To investigate the pathogenicity of Proteus mirabilis strains with varying lipopolysaccharide (LPS) structures.
- To characterize spontaneously agglutinating P. mirabilis isolates from patients with bacteriuria.
Main Methods:
- Isolation and characterization of Proteus mirabilis strains from bacteriuric patients.
- Analysis of lipopolysaccharides (LPS) using SDS-PAGE.
- Separation and chemical characterization of polysaccharide (PS) fractions.
- Evaluation of bacterial survival in a murine hematogenous infection model.
Main Results:
- Eight spontaneously agglutinating P. mirabilis strains were identified from 210 isolates.
- Strain characterization revealed S, Rc, Ra, and intermediate LPS forms.
- The P. mirabilis Rc mutant demonstrated significant kidney survival (≥2 weeks) in mice.
- A control Re mutant was rapidly eliminated (within 20 hours).
Conclusions:
- Proteus mirabilis strains with incomplete LPS structures can exhibit pathogenicity.
- The Rc LPS mutant shows prolonged survival in a murine kidney infection model.
- Incomplete LPS does not necessarily preclude P. mirabilis from causing infection.