title: Haemophilus influenzae carriage in children attending French day care centers: a molecular epidemiological study.
abstract: The nasopharyngeal Haemophilus influenzae flora of healthy children under the age of 3 years attending day care centers in three distinct French geographic areas was analyzed by sampling during two periods, spring 1999 (May and June) and fall 1999 (November and December). The average carrier rate among 1,683 children was 40.9%. The prevalence of capsulated H. influenzae carriers was 0.4% for type f and 0.6% for type e. No type b strains were found among these children, of whom 98.5% had received one or more doses of anti-Haemophilus b vaccine. Among the strains, 44.5% were TEM-type beta-lactamase producers and nine (1.3%) were beta-lactamase-negative ampicillin-resistant strains. Pulsed-field gel electrophoresis restriction patterns showed a large diversity with 366 SmaI patterns from 663 strains. Among the strains isolated during a given period, 33% were isolated simultaneously in more than one area. In each area, depending on the sampling period, 68 to 72% of the strains had new pulsotypes and persistence of 28 to 32% of the strains was noted. For the 297 beta-lactamase-producing strains, 194 patterns were found. The genomic diversity of these strains was comparable to that of the whole set of strains and does not suggest a clonal diffusion. Among the beta-lactamase-producing strains isolated in November and December, depending on the area, 66 to 73% had new pulsotypes with persistence of only 27 to 33% of the strains. In any given geographic area, colonization by H. influenzae appears to be a dynamic process involving a high degree of genomic heterogeneity among the noncapsulated colonizing strains.
authors.affiliation: Laboratoire de Microbiologie, Centre National de Référence des Haemophilus influenzae, Hôpital Purpan, Toulouse Cédex 9, France. dabernat.h@chu-toulouse.fr
authors.forename: Henri
authors.initials: H
authors.lastname: Dabernat
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Plisson-Sauné
authors.forename: Catherine
authors.initials: C
authors.lastname: Delmas
authors.forename: Martine
authors.initials: M
authors.lastname: Séguy
authors.forename: Gèneviéve
authors.initials: G
authors.lastname: Faucon
authors.forename: Roselyne
authors.initials: R
authors.lastname: Pélissier
authors.forename: Hélène
authors.initials: H
authors.lastname: Carsenti
authors.forename: Christian
authors.initials: C
authors.lastname: Pradier
authors.forename: Micheline
authors.initials: M
authors.lastname: Roussel-Delvallez
authors.forename: Joël
authors.initials: J
authors.lastname: Leroy
authors.forename: Marie-Jeanne
authors.initials: MJ
authors.lastname: Dupont
authors.forename: Frédéric
authors.initials: F
authors.lastname: De Bels
authors.forename: Pierre
authors.initials: P
authors.lastname: Dellamonica
mesh_terms: D015373:Bacterial Typing Techniques; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology*; D002656:Child Day Care Centers; D002675:Child, Preschool; D016521:Electrophoresis, Gel, Pulsed-Field; D005602:France; D006192:Haemophilus Infections / Q000382:microbiology*; D006193:Haemophilus influenzae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007223:Infant; D017720:Molecular Epidemiology; D009305:Nasopharynx / Q000382:microbiology; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D001618:beta-Lactamases