Characterisation of the CTX-M-15-encoding gene in Klebsiella pneumoniae strains from the Barcelona metropolitan area: plasmid diversity and chromosomal integration

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• 作者：Alicia Coelho ; Juan José ; Gonzá ; lez-Ló ; pez ; Elisenda Miró ; Carles Alonso-Tarré ; s ; Beatriz Mirelis ; Marí ; a Nieves Larrosa ; Rosa Marí ; a Bartolomé ; Antonia Andreu ; Ferra
• 关键词：bla_CTX-M-15 ; Replicon ; Klebsiella pneumoniae
• 刊名：International Journal of Antimicrobial Agents
• 出版年：2010
• 出版时间：July 2010
• 年：2010
• 卷：36
• 期：1
• 页码：73-78
• 全文大小：415 K

文摘

The localisation and genetic organisation of bla_CTX-M-15 were studied in 37 CTX-M-15-producing Klebsiella pneumoniae isolates collected from 2005 to 2008 within the Barcelona metropolitan area. Polymerase chain reaction (PCR)-based replicon typing and Southern hybridisations were used to identify the bla_CTX-M-15 location. The genetic environment was analysed by PCR mapping and sequencing, and transferability of bla_CTX-M-15 was evaluated by conjugation and transformation assays. The majority of the 37 isolates carried bla_CTX-M-15 in a plasmid location, frequently associated with the aac(6′)-Ib-cr gene. Plasmids encoding bla_CTX-M-15 carried three distinct replicons, i.e. IncFII, IncR and IncFIIk, the latter two not having been described previously in association with bla_CTX-M-15. Several of these plasmids were not self-transferable. Furthermore, in all isolates belonging to sequence type ST-1, bla_CTX-M-15 was found integrated into the K. pneumoniae chromosome. In all the studied isolates, the mobile element ISEcp1 was found upstream of bla_CTX-M-15, whereas IS26 was found inserted within ISEcp1 in several isolates, in previously unreported positions. In conclusion, these findings indicate that among K. pneumoniae strains isolated in the Barcelona metropolitan area, bla_CTX-M-15 is associated with diverse genetic elements, including the IncR and IncFIIk replicons, as reported for the first time here, and the chromosome.