Active copper- and zinc-containing superoxide dismutase in the cryptic genospecies of Haemophilus causing urogenital and neonatal infections discriminates them from Haemophilus influenzae sensu stricto.

The presence of active copper- and zinc-containing superoxide dismutase in isolates of the cryptic genospecies of Haemophilus, responsible for urogenital, neonatal, and mother-infant infections, can be used as a biochemical marker to discriminate them from H. influenzae sensu stricto strains.