Major subtypes of invasive Haemophilus influenzae from 1983 to 1985 in Atlanta, Ga.

We compared outer membrane protein (OMP) patterns of Haemophilus influenzae isolated in metropolitan Atlanta, Ga., from July 1983 to June 1985. Of 74 randomly selected H. influenzae serotype b, biotype I, isolates (24% of the total number of H. influenzae, and 32% of the total number of H. influenzae serotype b, biotype I, isolates), 66 (89.2%) had the same OMP pattern. Of the remaining eight, five (6.7%) had an identical OMP pattern. The other three isolates had separate and distinct patterns. A greater diversity of OMP patterns was found with H. influenzae serotype b, biotype II, and nonserotypeable H. influenzae. Of the 18 H. influenzae serotype b, biotype II, isolates (5.8% of the total number of H. influenzae isolates), 1 had an OMP pattern similar to that of the predominate biotype I OMP type, 6 (33% of the biotype II) had the same pattern, and 11 had heterogeneous patterns. Of the 19 recoverable, nonserotypeable biotype II isolates (6.8% of the total number of H. influenzae), 18 had different OMP patterns, and no pattern was similar to those observed with serotype b. These findings indicate that most H. influenzae strains isolated during this 2-year period were indistinguishable by serotype, biotype, or OMP patterns.