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Suckling mouse model of urinary tract infections caused by Escherichia coli
Abstract:
The role in the vesico-renal pathogenicity of Escherichia coli of mannose resistant fimbriae provisionally designated "119" has been studied in a suckling mouse model. Two to 3 days old mice were infected by route of the urinary bladder and the occurrence and character of the developing infection were investigated. (i) The fimbriated strain caused infection and inflammation of the bladder in almost 100%. In about 60% of the cases it lasted till the end of observations, the 35-37th day following inoculation. The washed, vortexed urinary bladder taken up in 5ml of saline contained a high number (10(6)-10(9)/ml) of bacteria, the urine was often cloudy, containing numerous leucocytes and epithelial cells packed with bacteria. The kidneys were soon involved and by the 23th ad 37th day gross changes were seen in about 25%. In 10%, a classical contracted kidney developed. (ii) The nonfimbriated derivate also caused acute or chronic urinary tract infection, but with a lower frequency and the number of bacteria was also lower by 3-4 log 10 exponents. The model seems to be promising for the study of bacterial infections of the urinary tract and perhaps also for elucidation of its immunological and therapeutic aspects.
Insights
Mannose-resistant fimbriae "119" from Escherichia coli cause severe bladder infections in mice. These fimbriae contribute to urinary tract infections and kidney damage, highlighting their role in pathogenicity.
Area of Science:
- Microbiology
- Pathogenesis
- Urology
Background:
- Escherichia coli is a common cause of urinary tract infections (UTIs).
- Fimbriae are bacterial appendages involved in adhesion and virulence.
- The specific role of mannose-resistant fimbriae '119' in vesico-renal pathogenicity requires elucidation.
Purpose of the Study:
- To investigate the role of mannose-resistant fimbriae '119' of Escherichia coli in the development of vesico-renal infections.
- To assess the pathogenicity of fimbriated and non-fimbriated E. coli strains in a suckling mouse model.
Main Methods:
- Infection of 2-3 day old mice via the urinary bladder with fimbriated and non-fimbriated E. coli strains.
- Monitoring of infection occurrence, duration, bacterial load, and pathological changes in the urinary tract and kidneys.
- Histopathological examination for kidney damage, including contracted kidney development.
Main Results:
- The fimbriated strain caused nearly 100% bladder infection and inflammation, persisting for up to 37 days.
- High bacterial loads (10^6-10^9/ml) and significant inflammatory markers were observed in infected bladders.
- Kidney involvement occurred, with gross changes in 25% and contracted kidney in 10% of cases.
- The non-fimbriated strain also caused UTIs, but with lower frequency and bacterial counts.
Conclusions:
- Mannose-resistant fimbriae '119' play a significant role in the pathogenicity of Escherichia coli in the urinary tract.
- The suckling mouse model is effective for studying bacterial UTIs and their immunological/therapeutic aspects.
- Fimbriae '119' contribute to both acute and chronic infection, as well as renal pathology.