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Virulence properties of Escherichia coli strains in patients with chronic pyelonephritis
Abstract:
In 50 Escherichia coli strains obtained from the bladder puncture urine of patients with chronic pyelonephritis, determinations of virulence properties were performed. All of the E. coli strains isolated from 26 acute episodes of pyelonephritis were found in the smooth form. 30% possessed K 1 antigen, 77% showed the ability to form hemolysin and 30% produced colicin V (aerobactin). Fimbriae (detected by mannose-resistant hemagglutination) were registered in 81%, and plasmids ranging between 50 and 70 Md were demonstrated in 70% of the bacteria. In contrast to this, only 70% of the E. coli strains isolated from 24 patients at an inactive stage of pyelonephritis were found in the smooth form; 10% of these encoded K 1 antigen, 20% hemolysin and 10% colicin V. Plasmids in the range 50 to 70 Md could be found in 30%. On the basis of multivariate analysis of variance and discriminant analysis, it was confirmed that uropathogenic strains possess several virulence properties, mannose-resistant hemagglutination being of particular importance.
Insights
Uropathogenic Escherichia coli strains from acute pyelonephritis exhibit higher virulence factors, including K1 antigen and hemolysin production, compared to those from inactive stages. Mannose-resistant hemagglutination is a key indicator of virulence in these E. coli strains.
Area of Science:
- Microbiology
- Urology
- Infectious Diseases
Background:
- Chronic pyelonephritis is a significant kidney infection often caused by Escherichia coli.
- Understanding the virulence factors of E. coli is crucial for diagnosing and treating urinary tract infections.
Purpose of the Study:
- To investigate and compare the virulence properties of Escherichia coli strains isolated from active versus inactive stages of chronic pyelonephritis.
- To identify key virulence determinants associated with uropathogenic E. coli.
Main Methods:
- Isolation and characterization of 50 Escherichia coli strains from patient urine samples.
- Assessment of virulence factors including K1 antigen, hemolysin production, colicin V (aerobactin), fimbriae (via mannose-resistant hemagglutination), and plasmid presence.
- Statistical analysis using multivariate analysis of variance and discriminant analysis.
Main Results:
- E. coli strains from acute pyelonephritis episodes showed significantly higher prevalence of K1 antigen (30%), hemolysin (77%), colicin V (30%), fimbriae (81%), and plasmids (70%) compared to strains from inactive stages.
- Strains from inactive stages had lower rates: K1 antigen (10%), hemolysin (20%), colicin V (10%), fimbriae (not specified but implied lower), and plasmids (30%).
- Mannose-resistant hemagglutination was identified as a particularly important virulence factor.
Conclusions:
- Uropathogenic E. coli strains possess multiple virulence properties that differentiate them between active and inactive pyelonephritis.
- The presence of specific virulence factors, notably fimbriae detected by mannose-resistant hemagglutination, is strongly associated with active urinary tract infections.