title: Role of non-capsulated Haemophilus influenzae as a respiratory pathogen in children.
abstract: During a 12-month surveillance period from 1981-1982, non-capsulated Haemophilus influenzae was detected in nasopharyngeal aspirates from 64 (14%) of the 449 children hospitalized for middle or lower respiratory infection. An antibody response to H. influenzae was indicated in 15(23%) of the 64 patients with H. influenzae present in nasopharyngeal aspirate and in 10 (3%) of the 385 patients with a negative finding. Thus, serological evidence of H. influenzae infection was demonstrated in 25 (6%) of all the 449 children with respiratory infection. Of 13 patients with cultures positive for H. influenzae acute otitis media, an antibody response was seen in only 4 (30%) patients. H. influenzae infection was associated with infections caused by other microbes in 20 children (80%), with viral infections in 60% and with pneumococcal infections in 24% of cases. An infection focus was present in 15 (79%) of the 25 patients with H. influenzae infection; pneumonia was present in 10 cases and acute otitis media in 9 cases. Non-specific laboratory evidence of bacterial infection was seen in 11 patients (58%); C-reactive protein was increased in 7 and erythrocyte sedimentation rate in 9 patients. It is concluded that non-capsulated H. influenzae is a genuine respiratory pathogen in children. H. influenzae infections appear to be secondary to preceding viral or other bacterial infections in children who are carriers of this strain.
authors.affiliation: Department of Paediatrics and Clinical Microbiology, Kuopio University Hospital, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Korppi
authors.forename: M L
authors.initials: ML
authors.lastname: Katila
authors.forename: J
authors.initials: J
authors.lastname: Jääskeläinen
authors.forename: M
authors.initials: M
authors.lastname: Leinonen
mesh_terms: D000293:Adolescent; D001826:Body Fluids / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D005387:Finland / Q000453:epidemiology; D006192:Haemophilus Infections / Q000453:epidemiology; D006193:Haemophilus influenzae / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D007223:Infant; D011159:Population Surveillance; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000382:microbiology*; D016036:Seroepidemiologic Studies