title: Low occurrence of 'non-haemolytic Haemophilus haemolyticus' misidentified as Haemophilus influenzae in cystic fibrosis respiratory specimens, and frequent recurrence of persistent H. influenzae clones despite antimicrobial treatment.
abstract: Non-influenzae commensal Haemophilus species of low pathogenicity may be difficult to discriminate from Haemophilus influenzae. We investigated the level of misidentifications in respiratory specimens from cystic fibrosis patients and evaluated the colonisation dynamics of genuine H. influenzae isolates. One hundred and ninety-two presumptive H. influenzae isolates were re-examined by assessment of marker genes sodC and fucK, and isolates with aberrant genotypes were subjected to multilocus sequence typing. Misidentifications (3%) were mainly caused by failure to identify porphyrin-synthesising strains, and only a single strain (0.5%) could be classified as 'non-haemolytic Haemophilus haemolyticus'. Sequential isolates of confirmed H. influenzae isolates from individual patients were typed by pulsed-field gel electrophoresis. Despite the routine prescription of antimicrobial therapy, the majority of H. influenzae isolates were identical with at least one of the strains cultured from the two preceding positive samples from the same patient.
authors.affiliation: Department of Clinical Microbiology, Aarhus University Hospital, DK-8200 Aarhus, Denmark.
authors.forename: Mette G
authors.initials: MG
authors.lastname: Fenger
authors.forename: Winnie
authors.initials: W
authors.lastname: Ridderberg
authors.forename: Hanne V
authors.initials: HV
authors.lastname: Olesen
authors.forename: Niels
authors.initials: N
authors.lastname: Nørskov-Lauritsen
mesh_terms: D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D003550:Cystic Fibrosis / Q000150:complications*; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D006190:Haemophilus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D006192:Haemophilus Infections / Q000188:drug therapy / Q000382:microbiology*; D006801:Humans; D007223:Infant; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D012008:Recurrence; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins