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Pili mediated agglutination of Serratia marcescens in human urine
Abstract:
Of 51 strains of Serratia marcescens isolated from patients with urinary or respiratory tract infections, 35 agglutinated in human urine. The agglutinating strains possessed numerous pili which were morphologically distinct from common pili or type I pili. The diameter of the pili was 3 nm and the average length was 0.3 micrometer. Electron microscopic examination showed that 80% or more of the cells of the agglutinating strains and 0 to 8% of the cells of the nonagglutinating strains were piliated. When an agglutinating strain was heated at 55 C for 10 min, it lost its agglutinating capacity and concomitantly its pili. These results suggest that the agglutination might occur because of interactions between the pili and some factors in human urine. The urinary slime appears to contain these agglutinating factors.
Insights
Pili on Serratia marcescens strains facilitate agglutination in human urine, suggesting a role for these structures in urinary tract infections. This interaction involves specific pili and urinary factors.
Area of Science:
- Microbiology
- Infectious Diseases
- Bacterial Pathogenesis
Background:
- Serratia marcescens is a bacterium associated with urinary and respiratory tract infections.
- The mechanisms underlying bacterial adherence and aggregation in host environments are crucial for infection development.
Purpose of the Study:
- To investigate the phenomenon of Serratia marcescens agglutination in human urine.
- To characterize the bacterial structures involved in this agglutination process.
Main Methods:
- Isolation and testing of Serratia marcescens strains from patient infections.
- Electron microscopy to visualize bacterial pili.
- Assessing agglutination capacity before and after heat treatment.
Main Results:
- 35 out of 51 Serratia marcescens strains agglutinated in human urine.
- Agglutinating strains possessed unique pili (3 nm diameter, 0.3 micrometer length).
- Heat treatment (55°C for 10 min) abolished both agglutination and pili presence.
Conclusions:
- The observed agglutination is mediated by specific pili on Serratia marcescens.
- These pili likely interact with factors present in human urine, possibly within urinary slime.
- This interaction may contribute to the pathogenesis of urinary tract infections caused by Serratia marcescens.