Open AccessChromosomally Encoded bla CMY-2 Located on a Novel SXT/R391-Related Integrating Conjugative Element in a Proteus mirabilis Clinical Isolate
Author(s) -
Sohei Harada,
Yoshikazu Ishii,
Tomoo Saga,
Kazuhiro Tateda,
Keizo Yamaguchi
Publication year - 2010
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.00111-10
Subject(s) - proteus mirabilis , biology , vibrio cholerae , salmonella enterica , mobile genetic elements , microbiology and biotechnology , transposable element , plasmid , genetics , escherichia coli , klebsiella pneumoniae , gene , bacteria , genome
Integrating conjugative elements (ICEs) are mobile genetic elements that can transfer from the chromosome of a host to the chromosome of a new host through the process of excision, conjugation, and integration. Although SXT/R391-related ICEs, originally demonstrated inVibrio cholerae O139 isolates, have become prevalent amongV. cholerae isolates in Asia, the prevalence of the ICEs among Gram-negative bacteria other thanVibrio spp. remains unknown. In addition, SXT/R391-related ICEs carrying genes conferring resistance to extended-spectrum cephalosporins have never been described. Here we carried out a genetic analysis of a cefoxitin-resistantProteus mirabilis clinical isolate, TUM4660, which revealed the presence of a novel SXT/R391-related ICE, ICEPmi Jpn1. ICEPmi Jpn1 had a core genetic structure showing high similarity to that of R391 and carriedxis andint genes completely identical to those of R391, while an IS10 -mediated composite transposon carryingbla CMY-2 was integrated into the ICE. A nucleotide sequence identical to the 3′ part of ISEcp1 was located upstream of thebla CMY-2 gene, and other genes observed aroundbla CMY-2 in earlier studies were also present. Furthermore, the nucleotide sequences of hot spot 2 and hot spot 4 in ICEPmi Jpn1 showed high similarity to that of hot spot 2 in SXTMO10 and with a part of the nucleotide sequence found inP. mirabilis ATCC 29906, respectively. ICEPmi Jpn1 was successfully transferred toEscherichia coli ,Klebsiella pneumoniae ,Salmonella enterica serovar Typhimurium, andCitrobacter koseri in conjugation experiments. These observations suggest that ICEs may contribute to the dissemination of antimicrobial resistance genes among clinically relevantEnterobacteriaceae , which warrants careful observation of the prevalence of ICEs, including SXT/R391-related ICEs.