Iron-suppressible production of hydroxamate by Escherichia coli isolates

Abstract

A total of 476 strains of Escherichia coli isolated from humans, pigs, cattle, poultry, potable water, or effluent were examined for iron-suppressible ability to produce hydroxamate. Isolates able to produce such material (Hyd' isolates) are presumed to be able to carry out hydroxamate-dependent transport of iron. The percentages of Hyd' isolates found among E. coli isolated from the feces of breast-fed babies (71%), adults (46%), milk-fed calves (32%), or poultry (28%) were significantly greater (P < 0.01) than the percentages isolated from potable water and effluent (6%) or from the feces of suckling piglets (6%), weaned pigs (6%), or weaned cattle (4%). The percentages of Hyd' isolates found among E. coli associated with diarrhea in humans (51%), weaned pigs (7%) or calves (25%) were not significantly different (P > 0.1) from those found among strains isolated from corresponding nondiarrheic hosts. Many of the E. coli isolated from cases of E. coli bacteremia in humans and poultry were Hyd' (64% and 83%, respectively). We conclude that ability to carry out hydroxamate-mediated transport of iron is widely distributed among natural isolates of E. coli but that the distribution of Abstr. Annu. Meet. Aust. Soc. Microbiol. 1981, C6, p54).

Absence of siderophore activity in Legionella species grown in iron-deficient media

“…more of these metals may interfere with the signal that triggers siderophore production. The synthesis of hydroxamates by two of the three E. coli strains used in this study was unexpected (strains K-12 and 0111:B4, Table 2); however, hydroxamate production has been previously reported in a number of E. coli strains isolated from a variety of sources (23). Preliminary evidence indicates that the hydroxamates in strain 0111:B4 are aerobactin and aerobactin side chain (unpublished data).…”

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

“…The present studies, by showing that the presence of aerobactin was associated with bacteremia and that aerobactin-positive strains survived better in heat-inactivated serum, support this hypothesis. In a study of hydroxamate-positive E. coli from different sources, Stuart et al (16) also observed a high incidence of hydroxamate-positive strains in isolates from the blood of humans and poultry. The bowel is the probable reservoir of E. coli for human infection, and an alternative explanation for our results might be that patients with bacteremia had more aerobactinpositive strains in the stool than patients with other infections.…”

Aerobactin-mediated iron uptake by Escherichia coli isolates from human extraintestinal infections

“…The aerobactin-mediated iron uptake system of Escherichia coli plasmid ColV-K30 (20) confers a significant selective advantage for bacterial growth in conditions of iron stress, such as those prevailing in the body of an experimentally infected animal (21,22). The clinical importance of the aerobactin system, however, and its ubiquity among pathogenic isolates of E. coli have not been systematically assessed, although small-scale studies have suggested a high incidence among strains isolated from the blood of patients with various diseases (11,16). In this paper we present the results of the first extensive systematic survey of clinical E. coli isolates.…”