Identification of a Klebsiella pneumoniae strain associated with nosocomial urinary tract infection

To differentiate between relapse of infection and reinfection of the urinary tract due to Klebsiella pneumoniae, 33 K. pneumoniae isolates collected from 20 patients with spinal cord injury (SCI) over 2 years were typed ibg genomic fingerprinting by repetitive-element PCR. Clinical isolates obtained from the same patients with recurrent episodes of urinary tract infection (UTI) revealed identical genomic fingerprints indicating relapse of UTI due to K. pneumoniae, despite appropriate antibiotic therapy, Seventeen isolates obtained from 8 of the 20 SCI patients shared a common genotype, termed RD6. Among non-SCI patients residing in other nursing units, the RDC genotype was found in 5 of 10 patients with K. pneumoniae UTI but in only 1 of 20 patients with K. pneumoniae infection that did not involve the urinary tract, suggesting a strong association of this genotype with UTI, All RD6 isolates exhibited strong adherence (greater than or equal to 50 adherent bacteria per cell) to HEp-2 cells, whereas other K. pneumoniae isolates generally did not adhere to or adhered very weakly to HEp-2 cells (less than or equal to 5 adherent bacteria per cell), Adherence was inhibited either by 4% D-mannose or by anti-type 1 fimbrial rabbit serum, These results suggest that the capacity of K. pneumoniae RD6 isolates to cause UTI may be mediated by its striking adherence to mammalian cells.