Degradation of albumin, haemopexin, haptoglobin and transferrin, by black-pigmented Bacteroides species.

Strains of six black-pigmented Bacteroides species and one un-named strain were examined for their ability to degrade the plasma proteins albumin, haemopexin, haptoglobin and transferrin. Strains of B. gingivalis were most effective, degrading all four plasma proteins at different rates. Strains of B. intermedius and B. asaccharolyticus showed intermediate activities, degrading different individual plasma proteins; strains of B. melaninogenicus, B. loeschei and B. denticola were least active, degrading only haemopexin. These findings are discussed in relation to the availability in tissue fluids of iron for bacterial growth.