title: Analysis of Haemophilus parasuis by multilocus enzyme electrophoresis.
abstract: The diversity among 40 Australian isolates and eight reference strains of Haemophilus parasuis was examined using multilocus enzyme electrophoresis. Thirty-four electrophoretic types (ETs) were recognized with a mean diversity per locus of 0.405. One Australian isolate was located in an ET separated by a considerable distance (> 0.8) from the rest of the isolates, suggesting that it may represent a different species or subspecies. The remaining 33 ETs formed two distinct divisions (A and B), separated from each other by a distance of 0.506. All 12 Australian isolates of serovar 5 plus the two reference strains for this serovar were included in Division A. The only other isolates present in this Division were Australian isolates of serovars 4 and 13 and two nontypeable isolates. Division B contained a diverse range of serovars-Australian isolates of serovars 1, 2, 7/10, 9 and 13 as well as the reference strains for serovars 1, 2, 3, 4, 8 and 9. These results supported other studies which demonstrated considerable diversity, and indicate that the population of H. parasuis may contain more than a single species or subspecies. There was considerable diversity even amongst isolates of the same serovar, indicating that serotyping is not a particularly suitable technique for strain typing in epidemiological studies.
authors.affiliation: Animal Research Institute, Yeerongpilly, Old, Australia. blackap@dpi.qld.gov.au
authors.forename: P J
authors.initials: PJ
authors.lastname: Blackall
authors.forename: D J
authors.initials: DJ
authors.lastname: Trott
authors.forename: V
authors.initials: V
authors.lastname: Rapp-Gabrielson
authors.forename: D J
authors.initials: DJ
authors.lastname: Hampson
mesh_terms: D000818:Animals; D001315:Australia; D015373:Bacterial Typing Techniques; D004586:Electrophoresis / Q000379:methods*; D014644:Genetic Variation; D006190:Haemophilus / Q000145:classification / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D012016:Reference Values; D013552:Swine