The distribution of genes encoding different iron acquisition systems in enteroaggregative Escherichia coli (EAEC) from adults with irritable bowel syndrome and from healthy controls was examined using a PCR assay. As many as 95.5% of EAEC carried the chuA gene coding for a haem receptor, and the majority of these strains also had yersiniobactin-encoding genes. Apart from yersiniobactin, enterobactin was the siderophore most frequently associated with EAEC among those strains examined. Genes encoding aerobactin and salmochelin siderophores were less frequent in the group of EAEC.