International dissemination of a multi-resistant IncA/C2 plasmid containing blaTEM-24, Tn21 and Tn1696 among epidemic and non-epidemic Enterobacteriaceae species

Abstract number: P2005

Novais A., Cantón R., Machado E., Curiao T., Baquero F., Peixe L., Coque T.M.

Objectives: TEM-24 is a widely disseminated ESBL mostly associated with epidemic Enterobacter aerogenes and Klebsiella spp. strains. The aim of this study was to analyse clonal and plasmid diversity among TEM-24 producing strains from 4 European countries.

Methods: Twenty eight TEM-24-Enterobacteriaceae isolates from Portugal, Spain, France and Belgium identified as E. aerogenes (n = 13), Escherichia coli (n = 6), Klebsiella pneumoniae (n = 6), Proteus mirabilis (n = 2) and Klebsiella oxytoca (n = 1) were studied (1998–2004). Only one isolate/patient was included. Clonal relatedness was established by PFGE and E. coli phylogenetic groups were searched by PCR. Antibiotic susceptibility testing and conjugation assays were performed using standard methods. Plasmid analysis included determination of size (Barton's method), incompatibility groups (rep-PCR, hybridisation, and sequencing) and comparison of RFLP patterns. Characterisation of integrons (class 1, 2 and 3), transposable elements and sul genes was performed by screening of sequences related to these elements (orf5, orf6, IS1326, IS1353, IS6100, tnpA, tnpR, tni, and mer), PCR overlapping based on Tn21 and Tn1696 sequences, and further sequencing.

Results:E. aerogenes, K. pneumoniae and P. mirabilis isolates corresponded to single PFGE types while E. coli were clonally unrelated (phylogroups D and A), all containing a 170–190kb-IncA/C2 conjugative plasmid carrying blaTEM-24 and conferring resistance to kanamycin, tobramycin, chloramphenicol, trimethoprim and sulfonamide. Different multi-resistant sequences were identified: i) In4 integron (aacA4) within Tn1696, ii) In0 derivative (dfrA1-aadA1) within Tn21 sequences, and iii) Tn3.

Conclusions: International dissemination of TEM-24 is associated with epidemic strains and an IncA/C2 epidemic plasmid containing multiple and genetic platforms conferring a multi-resistant phenotype. Interestingly, this trait was also conserved over the studied period.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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