A comparison of conventional and Minitek systems for biotyping Haemophilus influenzae

Two hundred pediatric isolates of Haemophilus influenzae from various sources were biotyped using the media described by Kilian in parallel with the Minitek system. There was an excellent correlation (97.7%) between the two systems. Ninety-five per cent of blood and cerebrospinal fluid (CSF) isolates were biotype I. Biotypes II and III were most frequent among isolates from sources other than blood and CSF. Production of beta-lactamase was limited to biotype II in the blood and CSF isolates, but was fairly evenly distributed among the biotypes from other sources. The Minitek system is an acceptable alternative to conventional media for biotyping H. influenzae.