Haemophilus influenzae can use human transferrin as a sole source for required iron.
Haemophilus influenzae grown on enriched medium containing protoporphyrin IX rather than hemin was iron starved by the addition of the chelator ethylenediamine di-o-hydroxyphenylacetic acid. Iron starvation could be overcome in each of 33 H. influenzae type b isolates by 30% Fe-saturated human transferrin but not by human lactoferrin. Among nontypeable H. influenzae, 28 of 35 isolates, including 2 of 3 systemic isolates, were able to utilize Fe-transferrin. None of 18 H. parainfluenzae isolates was able to use Fe-transferrin. Iron starvation of H. influenzae type b resulted in increased amounts of three membrane proteins of 94,000 to 98,000 daltons.
D001426:Bacterial Proteins / Q000032:analysis; D003470:Culture Media; D006193:Haemophilus influenzae / Q000254:growth & development / Q000378:metabolism*; D006801:Humans; D007501:Iron / Q000378:metabolism*; D007781:Lactoferrin / Q000378:metabolism; D008565:Membrane Proteins / Q000032:analysis; D012097:Repressor Proteins / Q000032:analysis; D014168:Transferrin / Q000378:metabolism*
D001426:Bacterial Proteins; D003470:Culture Media; D008565:Membrane Proteins; D012097:Repressor Proteins; D014168:Transferrin; D007501:Iron; D007781:Lactoferrin