title: Plasmid-encoded Tet B tetracycline resistance in Haemophilus parasuis.
abstract: The complete sequence of two plasmids, pHS-Tet (5.1 kb) and pHS-Rec (9.5 kb), isolated from Haemophilus parasuis strain HS1543 has been obtained. Plasmid pHS-Tet contains four open reading frames including a tet(B) tetracycline resistance gene which unusually did not have an associated tetR repressor gene. From a total of 45 H. parasuis isolates surveyed (15 international reference strains, 15 field isolates selected for their genetic diversity, and 15 recent Australian field isolates), 2 tetracycline-resistant field isolates (HS226 and HS1859) were identified. Analysis of three additional isolates from the same disease outbreak as strain HS1859 revealed a further tetracycline-resistant H. parasuis strain (HS1857, serovar 8) and a tetracycline-resistant Actinobacillus pleuropneumoniae strain (HS1861). An approximately 10.6-kb plasmid was identified in field isolate HS226 and outbreak strains HS1857, HS1859, and HS1861. Southern hybridization analysis of these plasmids showed that the Tet B determinant was present, and restriction digest comparisons suggest that these plasmids are related. This is believed to be the first report of native H. parasuis plasmids and Tet B-mediated tetracycline resistance in this microorganism.
authors.affiliation: School of Molecular and Microbial Sciences, University of Queensland, Brisbane 4072, Australia.
authors.forename: John F
authors.initials: JF
authors.lastname: Lancashire
authors.forename: Tamsin D
authors.initials: TD
authors.lastname: Terry
authors.forename: P J
authors.initials: PJ
authors.lastname: Blackall
authors.forename: Michael P
authors.initials: MP
authors.lastname: Jennings
mesh_terms: D016977:Actinobacillus pleuropneumoniae / Q000187:drug effects / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D015139:Blotting, Southern; D002847:Chromatography, Agarose; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D018274:Electroporation; D006190:Haemophilus / Q000187:drug effects* / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics*; D013753:Tetracycline Resistance / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes