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Bacterial interference in mixed infection in the rat bladder
K Watanabe1, Y Sakai, T Takezaki
1Department of Urology, Shinshu University School of Medicine, Matsumoto, Japan.
Abstract:
Interaction between Escherichia coli and Pseudomonas aeruginosa was studied in chronic bladder infection made in male Wistar rats by implanting a knotted silk thread holding organisms into the bladder. Strains isolated from patients were used. The number of organisms in bladder urine was measured 1 week after the inoculation. When E. coli and P. aeruginosa were inoculated simultaneously, P. aeruginosa grew less well than when inoculated alone. When P. aeruginosa was inoculated into the bladder colonized with E. coli, P. aeruginosa was almost always unable to grow in the bladder, while E. coli inoculated into the bladder colonized with P. aeruginosa was able to grow there in many animals. Bacteriocin activity had nothing to do with the results. These results indicate that E. coli interferes with the growth of P. aeruginosa in mixed infection in the bladder.
Insights
Escherichia coli (E. coli) inhibits Pseudomonas aeruginosa growth in mixed bladder infections. E. coli can colonize bladders with P. aeruginosa, but P. aeruginosa struggles to grow when E. coli is present.
Area of Science:
- Microbiology
- Urology
- Infectious Diseases
Background:
- Chronic bladder infections can involve polymicrobial colonization.
- Understanding bacterial interactions is crucial for treating complex urinary tract infections.
Purpose of the Study:
- To investigate the interaction between Escherichia coli and Pseudomonas aeruginosa in a chronic rat bladder infection model.
- To determine if E. coli inhibits P. aeruginosa growth during coinfection.
Main Methods:
- A chronic bladder infection model was established in male Wistar rats using implanted silk threads with bacterial strains.
- Bacterial counts in bladder urine were measured one week post-inoculation.
- Interactions were assessed through simultaneous inoculation and sequential inoculation experiments.
Main Results:
- P. aeruginosa exhibited reduced growth when coinoculated with E. coli compared to monoculture.
- E. coli colonization was successful when introduced into bladders already infected with P. aeruginosa.
- P. aeruginosa failed to establish significant growth when introduced into E. coli-colonized bladders.
- Bacteriocin activity did not correlate with the observed growth inhibition.
Conclusions:
- Escherichia coli actively interferes with the growth of Pseudomonas aeruginosa during mixed bladder infections.
- E. coli demonstrates a competitive advantage over P. aeruginosa in the bladder environment.
- These findings suggest a mechanism for E. coli dominance in polymicrobial urinary tract infections.