Nontypeable Haemophilus influenzae

NontypeableHaemophilus influenzaehave generally been regarded as relatively low-grade and infrequent pathogens. These organisms clearly play a role in causing otitis media in children and have been implicated in the pathogenesis of chronic bronchitis. Conflicting data have been presented as to whether nontypeableH influenzae, frequently cause acute exacerbations of chronic bronchitis. A careful review of articles on acute bacterial pneumonia shows few cases attributed to nontypeableH influenzaeand the reader is likely to conclude that either these organisms are not pathogenic or they should not be considered so unless they are isolated from blood or other enclosed tissue spaces. Our finding of pneumonia caused by nontypeableH influenzaein adults1stimulated a prospective study of patients with blood cultures positive forH influenzae. Data from four large hospitals in Houston and from one in Atlanta disclosed a striking and unexpected finding, namely, that nontypeableH influenzae