β-Lactam Resistance in <i>Haemophilus parasuis</i> Is Mediated by Plasmid pB1000 Bearing <i>bla</i> _ROB-1

Abstract

beta-Lactam resistance in Haemophilus parasuis is an emerging phenomenon that has not yet been characterized from a molecular perspective. Clinical high-level beta-lactam-resistant isolates from Spain bore a novel plasmid, pB1000, expressing a functionally active ROB-1 beta-lactamase. Pulsed-field gel electrophoresis was applied for the first time to H. parasuis and showed that beta-lactam resistance is due to clonal spread of a resistant strain, BB1018, bearing pB1000.