Haemophilus influenzae clinical isolates with plasmid pB1000 bearing blaROB-1: fitness cost and interspecies dissemination



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San Millán, Álvaro and Garcia Cobos, Silvia and Escudero, José Antonio and Hidalgo, Laura and Gutiérrez, Belén and Carrilero Aguado, Laura and Campos, José and González Zorn, Bruno (2010) Haemophilus influenzae clinical isolates with plasmid pB1000 bearing blaROB-1: fitness cost and interspecies dissemination. Antimicrobial agents and chemotherapy, 54 (4). pp. 1506-11. ISSN 1098-6596

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Official URL: http://aac.asm.org/content/54/4/1506.full


Plasmid pB1000 is a mobilizable replicon bearing the bla(ROB-1) beta-lactamase gene that we have recently described in Haemophilus parasuis and Pasteurella multocida animal isolates. Here we report the presence of pB1000 and a derivative plasmid, pB1000', in four Haemophilus influenzae clinical isolates of human origin. Pulsed-field gel electrophoresis showed unrelated patterns in all strains, indicating that the existence of pB1000 in H. influenzae isolates is not the consequence of clonal dissemination. The replicon can be transferred both by transformation and by conjugation into H. influenzae, giving rise to recipients resistant to ampicillin and cefaclor (MICs, > or =64 microg/ml). Stability experiments showed that pB1000 is stable in H. influenzae without antimicrobial pressure for at least 60 generations. Competition experiments between isogenic H. influenzae strains with and without pB1000 revealed a competitive disadvantage of 9% per 10 generations for the transformant versus the recipient. The complete nucleotide sequences of nine pB1000 plasmids from human and animal isolates, as well as the epidemiological data, suggest that animal isolates belonging to the Pasteurellaceae act as an antimicrobial resistance reservoir for H. influenzae. Further, since P. multocida is the only member of this family that can colonize both humans and animals, we propose that P. multocida is the vehicle for the transport of pB1000 between animal- and human-adapted members of the Pasteurellaceae.

Item Type:Article
Subjects:Medical sciences > Veterinary
ID Code:39692
Deposited On:09 Jan 2017 16:12
Last Modified:09 Jan 2017 16:12

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