title: Molecular epidemiology of Haemophilus influenzae type b in the Gambia.
abstract: One hundred two invasive and 64 noninvasive isolates of Haemophilus influenzae were collected in the course of a 2-year prospective field study on the epidemiology of H. influenzae meningitis in The Gambia. The isolates were serotyped, biotyped, and subtyped by outer membrane protein (OMP) profile analysis (OMP subtyping). H. influenzae meningitis was found to be caused by serotype b (95%). In invasive disease, serotype a, although present in the throat of healthy children, caused only occasionally (5.9%) disease. The distribution of biotypes of H. influenzae appeared to be very similar to that found outside The Gambia. A distinct pattern of OMP subtypes, different from other parts of the world, is prevalent in H. influenzae type b (Hib) in The Gambia. OMP subtypes 2, 4, 5, 8, and 9 were observed to be predominant. These subtypes, except subtype 2, have not been described. L subtypes (subtypes 2, 4, and 8) were associated with invasive disease, whereas non-L subtypes (subtypes 5 and 9) were found more often in healthy carriers (P less than 0.001). A significant difference in geographical distribution was found in subtypes of noninvasive Hib strains (P less than 0.05). We conclude that in The Gambia H. influenzae invasive disease is caused mainly by type b strains with a limited number of OMP subtypes, which are different from the subtypes found elsewhere in the world. These data are important for the surveillance of Hib disease in developing countries and are baseline data for a Hib polyribosyl-ribitolphosphate-conjugated vaccine trial in The Gambia. Alternative Hib OMP vaccines should include a set of representative OMPs.
authors.affiliation: Medical Research Council Laboratories, Fajara, The Gambia.
authors.forename: H A
authors.initials: HA
authors.lastname: Bijlmer
authors.forename: L
authors.initials: L
authors.lastname: van Alphen
authors.forename: L
authors.initials: L
authors.lastname: Geelen-van den Broek
authors.forename: B M
authors.initials: BM
authors.lastname: Greenwood
authors.forename: H A
authors.initials: HA
authors.lastname: Valkenburg
authors.forename: J
authors.initials: J
authors.lastname: Dankert
mesh_terms: D016667:Bacterial Capsules; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis; D015373:Bacterial Typing Techniques; D001428:Bacterial Vaccines / Q000627:therapeutic use; D004812:Epidemiologic Methods; D005714:Gambia / Q000453:epidemiology; D006192:Haemophilus Infections / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D018073:Haemophilus Vaccines; D006193:Haemophilus influenzae / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification; D006801:Humans; D011135:Polysaccharides, Bacterial / Q000627:therapeutic use; D012703:Serotyping
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine; D011135:Polysaccharides, Bacterial