Haemophilus influenzae polyarthritis in an adult: an analysis of serotype b strains

A 61-year-old man who presented with clinical features suggestive of septic arthritis was found to have acute septic polyarthritis due to Haemophilus influenzae (type b). The clinical and laboratory diagnoses of the case are presented, and the isolates of H. influenzae are characterized. Four isolates recovered from different sites had identical minimal inhibitory drug concentrations, outer membrane protein patterns, and genomic DNA restriction digests. These observations indicate that the disseminated infection arose from a single source. The patient developed antibody to several outer membrane proteins, particularly the P6 protein.