Objective: The genetic surroundings of blaCTX-M-15 in Escherichia coli recovered from faeces of travellers returning to the UK from overseas were compared with those among established UK strains to provide further insights into the spread of blaCTX-M-15 in the UK. Methods: From August 2006 to January 2008, 1031 faecal specimens were collected at the North West London NHS Trust from general practice patients with a clinical history of diarrhoea following recent international travel. Cefuroxime-resistant E. coli were isolated on cystine-lactose-electrolyte deficient agar and those that produced extended-spectrum b-lactamases (ESBLs) were identified by double disc synergy test (DDST). The molecular environments surrounding blaCTX-M-15 were investigated by PCR, DNA sequencing, gene cloning and northern blotting. Results: 182/1031 (18%) E. coli isolated from returning travellers gave a positive DDST, and were confirmed by PCR to produce CTX-M ESBLs; 174 (96%) had blaCTX-M-15, including 21 belonging to clone ST131. Among these 174 isolates, the environment upstream of blaCTX-M-15 consisted of either: (i) an intact ISEcp1 (n=108); (ii) various lengths of truncated ISEcp1 (n=58); or (iii) a 24 bp remnant of ISEcp1 (n=8). Two different promoters were found to transcribe blaCTX-M-15, resulting in different levels of cephalosporin resistance. Conclusion: E. coli with CTX-M-15 ESBL from returning travellers harboured previously seen UK blaCTX-M-15 genetic environments (intact or 24 bp remnant of ISEcp1) as well as blaCTX-M-15 genetic environments previously unseen in the UK (various lengths of truncated ISEcp1), which suggest overseas acquisition and highlight the difficulty of control in a time of population mobility and travel. © The Author 2011. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.
CITATION STYLE
Dhanji, H., Patel, R., Wall, R., Doumith, M., Patel, B., Hope, R., … Woodford, N. (2011). Variation in the genetic environments of blaCTX-M-15 in Escherichia coli from the faeces of travellers returning to the United Kingdom. Journal of Antimicrobial Chemotherapy, 66(5), 1005–1012. https://doi.org/10.1093/jac/dkr041
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