title: Nonencapsulated or nontypeable  Haemophilus influenzae  are more likely than their encapsulated or serotypeable counterparts to have mutations in their fucose operon.
abstract: Population biology of  Haemophilus influenzae  can be studied by multilocus sequence typing (MLST), and isolates are assigned sequence types (STs) based on nucleotide sequence variations in seven housekeeping genes, including fucK. However, the ST cannot be assigned if one of the housekeeping genes is absent or cannot be detected by the current protocol. Occasionally, strains of H. influenzae have been reported to lack the fucK gene. In this study, we examined the prevalence of this mutation among our collection of H. influenzae isolates. Of the 704 isolates studied, including 282 encapsulated and 422 nonencapsulated isolates, nine were not typeable by MLST owing to failure to detect the fucK gene. All nine fucK-negative isolates were nonencapsulated and belonged to various biotypes. DNA sequencing of the fucose operon region confirmed complete deletion of genes in the operon in seven of the nine isolates, while in the remaining two isolates, some of the genes were found intact or in parts. The significance of these findings is discussed.
authors: Vaccine Preventable Bacterial Diseases, National Microbiology Laboratory, 1015 Arlington Street, Public Health Agency of Canada, Winnipeg, MB R3E 3R2, Canada.
authors: Michelle L
authors: ML
authors: Shuel
authors: Kathleen E
authors: KE
authors: Karlowsky
authors: Dennis K S
authors: DK
authors: Law
authors: Raymond S W
authors: RS
authors: Tsang
mesh_terms: D000483:Alleles; D016667:Bacterial Capsules; D005643:Fucose / Q000235:genetics*; D006193:Haemophilus influenzae / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009154:Mutation; D009876:Operon / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012703:Serotyping
chemical_list: D005643:Fucose