Klebsiella pneumoniae-induced experimental pyelitis: the effect of piliation on infectivity.

The effect of bacterial piliation on the infectivity of Klebsiella pneumoniae in the renal pelvis was examined by means of piliated and nonpiliated variants derived from a single parent strain. Piliated-phase variants were significantly more infective as determined by viable counts of bacteria isolated from the kidneys at the time of sacrifice. In addition, scanning electron microscope was used to examine the renal pelvis for evidence of infection. Kidneys infected with piliated-phase organisms exhibited greater tissue damage -- both in the magnitude of tissue alterations observed and in the number of kidneys affected. Thus, it is concluded that piliation contributes to the ability of K. pneumoniae to infect the renal pelvis following reflux from the bladder.