Faecal Escherichia coli from patients with E. coli urinary tract infection and healthy controls who have never had a urinary tract infection.
Urinary tract infections (UTIs) are primarily caused by Escherichia coli with the patient's own faecal flora acting as a reservoir for the infecting E. coli. Here we sought to characterize the E. coli faecal flora of UTI patients and healthy controls who had never had a UTI. Up to 20 E. coli colonies from each rectal swab were random amplified polymorphic DNA (RAPD) typed for clonality, dominance in the sample and correlation to the infecting UTI isolate in patients. Each distinct clone was phylotyped and tested for antimicrobial susceptibility. Eighty-seven per cent of the UTI patients carried the infecting strain in their faecal flora, and faecal clones causing UTI were more often dominant in the faecal flora. Patients had a larger diversity of E. coli in their gut flora by carrying more unique E. coli clones compared to controls, and patient faecal clones were more often associated with multidrug resistance compared to controls. We found a similar phylotype distribution of faecal clones from UTI patients and healthy controls, including a large proportion of B2 isolates in the control group. Faecal-UTI isolates from patients were more often associated with multidrug resistance compared to faecal-only clones, indicating a link between UTI virulence and antimicrobial resistance. Intake of any antibiotic less than 6 months prior to inclusion in the experiment occurred significantly more in patients with UTI than in controls. In contrast, presence of an intrauterine device was significantly more common in controls indicating a protective effect against UTI. In conclusion, healthy controls have a large proportion of potentially pathogenic E. coli phylotypes in their faecal flora without this causing infection.
Department of Clinical Microbiology, Hvidovre Hospital, Kettegård Alle 30, 2640 Hvidovre, Denmark.|Department of Microbiology and Infection Control, Statens Serum Institut, Artillerivej 5, 2300 København S, Denmark.
Karen L
KL
Nielsen
Haslev Lægecenter, Nygade 42, 4690 Haslev, Denmark.
Pia
P
Dynesen
Lægehuset Ellemarksvej, Ellemarksvej 4, 4600 Køge, Denmark.
Preben
P
Larsen
Department of Clinical Microbiology, Hvidovre Hospital, Kettegård Alle 30, 2640 Hvidovre, Denmark.|Department of Microbiology and Infection Control, Statens Serum Institut, Artillerivej 5, 2300 København S, Denmark.
Niels
N
Frimodt-Møller
D000328:Adult; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000382:microbiology*; D005243:Feces / Q000382:microbiology*; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058889:Molecular Typing; D019105:Random Amplified Polymorphic DNA Technique; D014552:Urinary Tract Infections / Q000382:microbiology*