Table 1.

Bacterial strains and plasmids used in this study

Strain or plasmidDescription or phenotypeReference(s) or source
H. influenzae strains
 DL26Wild-type Hib strain that expresses the HxuA protein and can utilize heme-hemopexin 16
 DL42Wild-type Hib strain that expresses the HxuA protein and can utilize heme-hemopexin 4, 5
 DL42.107dDL42 mutant with a NotI linker inserted into the hxuA structural gene; this strain does not express HxuA and cannot utilize heme-hemopexin 17
 DL42.61DL42.107d with a cat cartridge inserted into the NotI site within the hxuAgene 5
 760705Wild-type Hib strain that does not express the HxuA protein and does not utilize heme-hemopexin 4, 47
 N182Wild-type NTHI strain that expresses the HxuA protein and can utilize heme-hemopexin 4
E. colistrains
 RR1Host strain for recombinant plasmids 38
 RR1(pBR322)Recombinant strain that does not release HxuA into the CS38
 RR1(pHX1-6)Recombinant strain that releases HxuA into the CSThis study
Plasmids
 pBR322Cloning vector, Ampr Tetr 38
 pHX1-6pBR322 with a 13.6-kb insert of H. influenzae DL42 chromosomal DNA containing the hxuCBAgene cluster 5, 17