Fachbereich Veterinärmedizin



    Analysis of blaSHV-12-carrying Escherichia coli clones and plasmids from human, animal and food sources (2017)

    Zeitschriftenartikel / wissenschaftlicher Beitrag
    Alonso, Carla Andrea
    Michael, Geovana Brenner
    Li, Jun
    Somalo, Sergio
    Simón, Carmen
    Wang, Yang
    Kaspar, Heike
    Kadlec, Kristina
    Torres, Carmen
    Schwarz, Stefan (WE 7)
    The Journal of antimicrobial chemotherapy; 72(6) — S. 1589–1596
    ISSN: 0305-7453
    DOI: 10.1093/jac/dkx024
    Pubmed: 28333184
    Institut für Mikrobiologie und Tierseuchen

    Robert-von-Ostertag-Str. 7-13
    Gebäude 35
    14163 Berlin
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    Abstract / Zusammenfassung

    Objectives: This study aimed at characterizing 23 Escherichia coli isolates from various sources and their respective blaSHV-12-carrying plasmids and sequencing one of these plasmids completely.

    Methods: Isolates were typed by XbaI-PFGE, MLST and PCR-based phylotyping. Transformed blaSHV-12-carrying plasmids were examined by replicon typing, S1-nuclease, conjugation, EcoRI-HindIII-BamHI digests and plasmid MLST. Co-located resistance genes and integrons as well as the blaSHV-12 genetic environment were analysed by PCR and sequencing. One IncI1 plasmid was sequenced completely using HiSeq 2500 and gap closure by PCRs and Sanger sequencing.

    Results: Among the 23 SHV-12-positive E. coli, some isolates from different sources showed the same characteristics: ST23/phylogroup A (human, dog, livestock), ST57/D (wild bird, chicken meat) and ST117/D (chicken meat, chicken). All blaSHV-12 genes were horizontally transferable via 30–120 kb plasmids of incompatibility groups IncI1 (n = 17), IncK (n = 3), IncF (n = 1), IncX3 (n = 1) and a non-typeable plasmid. IncK plasmids, indistinguishable in size and restriction patterns, were found in isolates from different sources (ST57/D, meat; ST131/B2, meat; ST57/B1, dog). The IncI1-blaSHV-12-carrying plasmids were mostly assigned to plasmid ST (pST) 26 and pST3. Three plasmids showed novel pSTs (pST214, pST215). The majority of the IncI1 transformants exhibited resistance to β-lactams, chloramphenicol and streptomycin (in relation with a class 1 integron containing an estX-psp-aadA2-cmlA1-aadA1-qacI gene cassette array), and to tetracycline. A novel blaSHV-12 environment was detected and whole plasmid sequencing revealed a Tn21-derived-blaSHV12-ΔTn1721 resistance complex.

    Conclusions: Results from this study suggest that the dissemination of blaSHV-12 genes occurs by vertical (clonal) and horizontal transfer, the latter mainly mediated through IncI1 multidrug-resistance plasmids.