1041 EPIDEMIOLOGY OF HAEMOPHILUS INFLUENZAE DISEASE DETERMINED BY OUTER MEMBRANE PROTEIN COMPOSITION

Abstract

The outer membrane protein composition of 50 disease isolates of H. influenzae, including strains of all 6 serotypes as well as untypable strains, has been determined by SDS-PAGE. Results show the existence of considerable strain variation in the mobility of some, but not all, of the proteins. For example, the 28 type b strains examined could be classified into 8 subtypes according to differences in the mobilities of 4 of the 7 major outer membrane proteins. Untypable strains showed even greater diversity. Using these differences as an epidemiological tool, we have found the following: (1) A recent outbreak of type b meningitis involving 17 Rochester area children over a 6-week period was caused by at least 5 different strains, indicating that a single “killer” strain was not responsible for the epidemic. (2) In all 7 patients examined, type b isolates from different anatomic sites in the same patient were identical, suggesting that a single bacterium initiated the disease. (3) Isolates from a patient experiencing a repeat type b infection were identical, suggesting that the same strain was responsible for reinfection. In addition to these findings we have also discovered: (1) Some outer membrane proteins are common to all strains. (2) Children recovering from systemic type b disease raise serum antibodies to outer membrane proteins. Studies are currently in progress to identify the particular immunogenic proteins.