Association of hydroxamate siderophore (aerobactin) with Escherichia coli isolated from patients with bacteremia

Abstract

Clinical isolates of Escherichia coli were examined for the presence of hydroxamate siderophore (aerobactin). The incidence of aerobactin-positive strains of E. coli from the blood was greater than the incidence of these strains isolated from other sites. The presence of aerobactin and the virulence of strains of E. coli in urinary tract infection were also examined in mice. The presence of aerobactin in the strains of E. coli correlated with virulence as measured by proportion of deaths but not with renal infection. These results suggest that the presence of aerobactin may be a significant factor in the invasion of the blood stream.

Aerobactin-mediated iron uptake system in intestinal Escherichia coli

“…The latter number is in the same range as reported for normal fecal E. coli isolates. The percentage of E. coli diarrheal strains which express the aerobactin receptor is similar to the aerobactin-positive E. coli isolated from extraintestinal infections [8,25].…”

The aerobactin iron uptake system in enteropathogenic Escherichia coli: evidence for an extinct transposon

“…In the case of E. coli the aerobactin system is most frequently found among strains from neonatal meningitis, septicaemia and urinary tract infections [13,14]. Indeed, in a particular group of strains from human pyelonephritis the frequency of aerobactin synthesis was as high as that of P-fimbriae and higher than that of haemolysin, both recognised virulence-enhancing factors in uropathogenic E. coli [15][16][17].…”

Production by Escherichia coli isolates of siderophore and other virulence factors and their pathogenic role in a cutaneous infection model

“…Bacterial virulence is multifactorial, and the virulence characteristics of E. coli have been studied in UTIs and bacteraemia [1][2][3]. Among the proposed virulence factors are fimbrial adhesins, haemolysin, siderophores, serum resistance and inactive serum resistance [4][5][6][7][8]. Iron compounds are known to increase the growth of bacteria, and enteric bacteria produce a catechol-type siderophore, enterobactin, and a hydroxamate-type siderophore, aerobactin, under conditions of iron starvation in vitro [9][10][11].…”

“…The role of siderophores was investigated in the present study with the subcutaneous route, as it was quick, easy and practical. The role of aerobactin and other virulence factors in pathogenicity has been studied previously in mice [8,18,19]. Torres et al [19] suggested that TonB was required for iron uptake by uropathogenic E. coli in a mouse model of UTI, as TonBnegative mutant isolates showed reduced virulence.…”

“…E. coli A + isolates showed more growth than E + isolates, but the difference was not statistically significant. Montgomerie et al [8] suggested that aerobactin is a more significant factor in bacteraemia in mice than enterobactin. In another study, E. coli isolates were assigned to three groups according to LD 50 .…”