Simultaneous recovery of beta-lactamase-negative and beta-lactamase-positive Haemophilus influenzae type b from cerebrospinal fluid of a neonate.

A case of Haemophilus influenzae type b meningitis in a neonate from whom both a beta-lactamase-negative and a beta-lactamase-positive strain were isolated simultaneously is reported. Both bacteriology laboratory technicians and clinicians should be aware of this phenomenon when performing sensitivity tests on H influenzae isolates or treating patients with serious H influenzae infection.