To the Editor.—In a recent report,1 Hable et al claimed that seven of ten cases of Hemophilus meningitis studied during a 16-month period at the Mayo Clinic were due to H parainfluenzae, whereas only three were due to H influenzae (the two organisms distinguished by their requirement for hemin, or X factor, with no mention of serologic identification). We therefore decided to try to confirm this surprising finding in Pittsburgh.
The organisms recovered from the spinal fluid of 44 consecutive patients with Hemophilus meningitis admitted to Children's Hospital of Pittsburgh during an eight-month period (October 1971 to June 1972) were tested for X and V factor requirements (using BBL Taxo X and V strips on heart infusion agar). All 44 of these spinal fluids yielded Hemophilus organisms which "satellited" around the XV strip but not around either the V strip or the X strip. The 44 organisms were