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.

Virulence factors in Escherichia coli urinary tract infection

“…However, using more-sensitive methods and morecareful patient selection, others have found evidence of fimbriation and adherence in bacteria in a substantial proportion of urine specimens from infected patients (313,390,427) (181,198,338,469,470,472,509,512,518,527). Hemagglutination testing yields similar results, with the highest proportion of MRHA strains among pyelonephritis patient isolates (50 to 81%) and progressively lower proportions among cystitis patient isolates (17 to 52%), ABU patient isolates (11 to 19%), and fecal isolates (2 to 29%) (48, 49,102,139,162,181,315,316,354,399,423,509,566). This evidence indicates that mannose-resistant uroepithelial-cell adherence and MRHA are characteristic of strains with an increased ability to cause UTI (especially the more clinically severe forms) and suggests that these properties may contribute directly to urovirulence.…”

“…Kl is the most commonly encountered capsular type among both urinary and fecal strains (406). The prevalence of fecal carriage of Kl strains increases with age, climbing from 22% of premature infants to 45% of adult 21/193 (11) 9/50 (18) 77 14/155 (9) 10/170 (6) 4/59 (7) 28/384 (7) 17/233 (7) 139 9 Includes patients with known compromising conditions. d Because of differences in study design, methods, definitions, and populations in different studies, totaled results must be interpreted with caution.…”

Molecular Characterization of the Escherichia coli Asymptomatic Bacteriuria Strain 83972: the Taming of a Pathogen

“…Acute pyelonephritis and asymptomatic bacteriuria (ABU) represent the two extremes of UTI. Acute pyelonephritis is a severe systemic infection caused by uropathogenic Escherichia coli (UPEC) (6,7,29,31). ABU, on the other hand, is an asymptomatic carrier state in which patients may carry Ͼ10…”

Escherichia coli hemolysin is a potent inductor of phosphoinositide hydrolysis and related metabolic responses in human neutrophils.

“…Approximately 50% ofE. coli isolates causing extraintestinal infections in humans produce Hly; this agent represents one of the most prevalent bacterial exotoxins encountered in humans (1,3,4,(7)(8)(9). Its pathogenetic relevance has been established in animal models with the use of genetically engineered bacterial strains (1,7,10).…”

“…Its pathogenetic relevance has been established in animal models with the use of genetically engineered bacterial strains (1,7,10). An analogous role in human infections has been inferred from the high association of hemolysin production with disease, including pyelonephritis and septicemia (8,9).…”