Haemophilus influenzae: Then and now

Abstract

Haemophilus influenzae has long been recognised as a major cause of serious infection and mortality in children less than 5 years old. Prior to the introduction of Haemophilus influenzae type b (Hib) immunisation, the incidence of a child suffering an invasive Haemophilus infection was 20-50/100,000 in industrialised countries and up to ten times higher in developing regions. The introduction of a Hib vaccine programme results in a rapid and dramatic decline in the incidence of Hib infection in the susceptible childhood population. For example, within two years of the introduction of routine Hib vaccination of infants in the UK, the risk of serious Hib infection had fallen from 1:600 to 1:30,000 by 5 years of age. Many other European countries have introduced, or are in the process of introducing, a routine Hib immunisation programme. Because the epidemiology of Haemophilus influenzae infection is changing so dramatically, it is opportune to review Haemophilus influenzae as it was perceived in the pre-vaccine era (the past) and during vaccine implementation (the present), and how its role may change in the post-vaccination era (the future). This review will summarise the historical landmarks that have led to our present-day understanding of Haemophilus influenzae pathogenicity, the concerns about antibiotic resistance, the features of the host immune response to Haemophilus influenzae, and the introduction of the Hib vaccine. Furthermore, the possible importance of this organism in the future will be discussed.

Antimicrobial resistance patterns of Haemophilus influenzae isolated from patients with meningitis in São Paulo, Brazil

“…Meningitis, especially in infants, young children and in the elderly, is the most serious clinical manifestation of invasive disease caused by Haemophilus influenzae (1,2). Substantial declines in invasive Haemophilus influenzae type b diseases have been reported in many countries where routine vaccination against H. influenzae type b has been implemented (3)(4)(5)(6).…”

Diversity of β-Lactam Resistance-Conferring Amino Acid Substitutions in Penicillin-Binding Protein 3 of Haemophilus influenzae

“…In subgroup IIa (n ‫؍‬ 5; H. influenzae ATCC 49247), the only observed substitution was Lys-526 for Asn-526; in subgroup IIb (n ‫؍‬ 56), Val-502 was substituted for Ala-502 (n ‫؍‬ In spite of the widespread use of the anti-Haemophilus b vaccine in the industrialized countries and the decreased incidence of invasive diseases (18), Haemophilus influenzae remains a key species in bronchopulmonary and ear, nose, and throat (ENT) infections in both adults and children. These diseases are most often caused by noncapsulated strains (10,14). Treatment of such infections can be severely affected by antibiotic resistance.…”

Emergence of Nonencapsulated and Encapsulated Non-b-Type Invasive Haemophilus influenzae Isolates in Portugal (1989-2001)

“…Haemophilus influenzae serotype b (Hib) was, until the introduction of a vaccine, responsible for most cases of invasive disease (10). Accurate antibiotic treatment is required as quickly as possible.…”