Epidemiology and Infection

Relationship between Escherichia coli strains causing urinary tract infection in women and the dominant faecal flora of the same hosts

E. MORENO a1, A. ANDREU a1, T. PÉREZ a1, M. SABATÉ a1, J. R. JOHNSON a2 and G. PRATS a1c1
a1 Microbiology Department, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain
a2 Mucosal and Vaccine Research Center, Veterans Affairs Medical Center, and Department of Medicine, University of Minnesota, Minneapolis, MN, USA

Article author query
moreno e   [PubMed][Google Scholar] 
andreu a   [PubMed][Google Scholar] 
perez t   [PubMed][Google Scholar] 
sabate m   [PubMed][Google Scholar] 
johnson jr   [PubMed][Google Scholar] 
prats g   [PubMed][Google Scholar] 


To clarify whether prevalence or special pathogenicity is more important in determining urinary tract infection (UTI) causation, we compared the biotype, phylogenetic group, and virulence genes of Escherichia coli urine strains from 11 women with acute lower UTI with those of the host's dominant intestinal E. coli strain(s). Twenty-one unique E. coli clones were identified. For three women, the single faecal clone identified was also the host's urine clone, whereas for eight women faecal samples yielded 1 or 2 distinct non-urine clones (total, n=10), either with (n=3) or without (n=5) the concurrent urine clone. The eight urine clones from the latter eight women exhibited significantly greater inferred virulence, according to virulence gene content and phylogenetic background, than did the hosts' 10 corresponding ‘faecal only’ clones. In contrast, the three urine clones that were detected as the host's sole faecal clone exhibited significantly lower inferred virulence than the other eight urine clones, and were statistically indistinguishable from the 10 ‘faecal only’ clones. In conclusion, special pathogenicity is an important determinant of UTI pathogenesis in women, although prevalence may occasionally allow less virulent strains to cause UTI.

(Accepted December 1 2005)
(Published Online January 26 2006)

c1 Servicio de Microbiología, Hospital Vall d'Hebron, Pg. Vall d'Hebron 119-129, 08035 Barcelona, Spain. (Email: gprats@vhebron.net)