Virulence characteristics of Escherichia coli causing asymptomatic bacteriuria

K. Gupta, A. E. Stapleton, T. M. Hooton, C. L. Fennell, M. Samadpour, W. E. Stamm

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Little is known about the virulence characteristics of E. coli strains that cause asymptomatic bacteriuria (ASB) in adult women, or of the relationship between these strains and those that cause symptomatic cystitis (CYS). To address these issues, we studied 122 E. coli isolates obtained from 63 prospectively followed college age women who had ASB with >105 cfu/ml of E. coli either once or in repeated samples 1-7 weeks apart. We compared these isolates with 78 E. coli strains that caused CYS in the same patient group. We employed a novel PCR method to identify the prevalence of the three allelic variants of the adhesin molecule papG: papGJ96, papGlA2, and prsGJ96 (Class I, II, and III, respectively). We also tested the strains for mannose resistant hemagglutination (MRHA) of human and sheep red blood cells and hemolysin. Results: The overall prevalence of papG was similar in ASB and CYS isolates, as was the distribution of pap classes and prevalence of hemolysin and MRHA. The same papG class was persistent in 90% of women with consecutive ASB episodes and 94% of women with both ASB and CYS episodes. Further, micro-restriction fingerprinting of 32 strains (28 ASB and 4 UTI) from 6 women confirmed that the same strain persisted and caused consecutive ASB and/or ASB and CYS in each woman. We conclude that the virulence characteristics of E. coli strains causing ASB in young women are similar to those causing CYS, and that in women with ASB and CYS, these strains are likely to be genetically identical in a given patient. ASB CYS (n=122) (n = 78) papG+ 39% 41% Class I 0% 0% Class II 18% 15% Class III 20% 19% Class I/III 0% 6% Hemolysin 37% 36% MRHA 59% 53%.

Original languageEnglish (US)
Number of pages1
JournalClinical Infectious Diseases
Issue number2
StatePublished - Dec 1 1997
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases


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