Iron utilization studies in Citrobacter species.
Seventy-one strains of Citrobacter were screened for iron scavenging mechanisms by biologic and chemical assays. Essentially all citrobacteria (70/71) were found to elaborate enterobactin-like siderophores by both biologic and chemical assays, however only c. koseri (C. diversus) was found to produce aerobactin. The concentration of ethylenediamine di(o-hydroxyphenylacetic acid) (EDDA) required to inhibit the growth of individual Citrobacter strains by depleting free iron ranged from 250 micrograms/ml to 100 micrograms/ml. Iron utilization studies of selected citrobacter isolates indicated that hemin and hematin could reverse the effects of iron limitation on growth under iron-stressed conditions (1000 micrograms/ml of EDDA). Two C. koseri strains grown under iron-restricted conditions showed similar changes in their whole cell protein profiles including induction of high molecular mass proteins (72-83 kDa) which may play a role in iron acquisition under iron-stressed conditions. The collective results support an additional virulence-associated mechanism for C. koseri strains which may help explain the greater pathogenic potential this group has for causing serious extraintestinal disease in humans.
Khashe
S
S
Division of Communicable Disease Control, California Department of Health Services, Berkeley 94704-1011, USA.
Janda
J M
JM
D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D002954:Citrobacter / Q000187:drug effects / Q000378:metabolism* / Q000472:pathogenicity; D004492:Edetic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004756:Enterobacteriaceae Infections / Q000209:etiology; D004758:Enterobactin / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D008970:Molecular Weight; D017262:Siderophores / Q000378:metabolism; D014774:Virulence
D001426:Bacterial Proteins; D002614:Chelating Agents; D006877:Hydroxamic Acids; D017262:Siderophores; C031819:aerobactin; D004758:Enterobactin; C026058:EDDA; D004492:Edetic Acid; D007501:Iron