STAPHYLOCOCCAL IRON REQUIREMENTS, SIDEROPHORE PRODUCTION, AND IRON-REGULATED PROTEIN EXPRESSION

Despite the ability of staphylococci to grow in iron-restricted condit ions in vivo, their iron requirements and the mechanisms possessed by them for the uptake of iron are poorly understood. Many bacteria are k nown to produce siderophores. By using the chrome azurol S universal m ethod for the detection of siderophores, all 14 isolates of Staphyloco ccus aureus tested grew well under conditions of iron restriction and produced iron-regulated siderophore in large quantities, while all 19 isolates of coagulase-negative staphylococci (CoNS) grew poorly under conditions of iron restriction and produced low levels of iron chelato r. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles of S. aureus isolates revealed altered protein patterns due to iron re striction, while altered profiles were not seen in the CoNS group. The ability to grow in iron-restricted conditions, possibly with the assi stance of siderophore-mediated iron uptake, may contribute to the incr eased pathogenicity of S. aureus when compared with that of the CoNS.