Relationship of type 1 pilus expression in Escherichia coli to ascending urinary tract infections in mice

Abstract

The role of type 1 pili and P adhesins during the in vivo growth of Escherichia coli inoculated into the urethras of BALB/c mice was studied. Strains which produced type 1 pili when grown in broth but lost this trait when grown on agar (regulated variants) were tested. Broth-grown organisms colonized the bladder of every animal tested, with counts of 103 to 104 viable organisms recovered from bladder homogenates. Agar-grown organisms gave lower rates of infection and the number of viable organisms recovered from bladders was significantly reduced. The degree of inoculum piliation influenced bladder colonization in a direct way: as piliation increased, the number of bacteria recovered from bladders also increased. After intraurethral inoculation, all of the bladders and 44% of the kidneys were colonized on day 1, and by day 5, 94% of the bladders and 16% of the kidneys were positive. Hemagglutination titers remained high for the bladder isolates, but the organisms colonizing the kidneys became significantly less piliated with time. Bacteriuria was unrelated to bladder or renal colonization. Strains that demonstrated random phase variation of type 1 pili during growth on agar produced similar colonizations of the urinary tract with broth-and agar-grown inocula. Strains that produced only P adhesins were less effective in colonizing the urinary tract than were type 1 piliated organisms. Other strains which did not produce pili only minimally colonized the bladder. The results suggest that type 1 pili play an essential role in ascending infections of the urinary tract.

Hemagglutinating and adherence properties of Staphylococcus saprophyticus: epidemiology and virulence in experimental urinary tract infection of rats

“…The fact that virulence of non-hemagglutinating strain 9325 was not dependent on growth conditions supports this hypothesis. A similar situation exists in E. coli, since expression of type 1 pili, which is dependent on growth conditions, also influences colonization of kidney or bladder in mice [15]. Our experiments further suggest that animal studies on the hemagglutinin of S. saprophyticus should use liquid grown bacteria.…”

Do type 1 fimbriae promote inflammation in the human urinary tract?

“…Uroepithelial cells from infection prone patients have previously been shown to bind higher numbers of adherent bacteria than cells from controls (Fowler and Stamey, 1977). This effect has been confirmed for P fimbriated E. coli (Lomberg et al ., 1986) but preferential binding of type 1 fimbriated E. coli to patient cells remains to be unequivocally demonstrated (Schaeffer et al ., 1987).…”

Orientational control of fimE expression in Escherichia coli

“…Fimbrial adhesins, such as type 1 fimbriae, play a key role in the attachment of Gram-negative bacteria to the host mucosa (Brinton, 1959;Keith et al, 1986;Sokurenko et al, 1994). In Escherichia coli, type 1 fimbriae are thought to facilitate host-to-host transmission, as well as to be a virulence factor in urinary tract infections (cystitis) (Schaeffer et al, 1987;Connel et al, 1996;Langermann et al, 1997). Recent studies show that bacterial attachment via type 1 fimbriae can induce IL-8 secretion in mucosal cells, and that the adhesin is both necessary and sufficient for invasion of uroepithelial cells (Godaly et al, 1998;Martinez et al, 2000).…”