Different clinical isolates of Acinetobacter baumannii, typed by plasmid profile, were able to grow in iron-chelated medium by secreting iron-regulated siderophores. This iron-scavenging phenotype was associated with the production of iron-repressible catechol. Siderophore utilization bioassays showed the presence of 2,3-dihydroxybenzoic acid in the growth medium, and neither enterobactin nor aerobactin was detected in culture supernatants obtained under iron-deficient conditions.