Open AccessWhole-Genome Analysis of Salmonella enterica Serovar Typhimurium T000240 Reveals the Acquisition of a Genomic Island Involved in Multidrug Resistance via IS 1 Derivatives on the Chromosome
Author(s) -
Hidemasa Izumiya,
Tsuyoshi Sekizuka,
Hideo Nakaya,
Masumi Taguchi,
Akio Oguchi,
Natsuko Ichikawa,
Rika Nishiko,
Shuji Yamazaki,
Nobuyuki Fujita,
Haruo Watanabe,
Makoto Ohnishi,
Makoto Kuroda
Publication year - 2011
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.01215-10
Subject(s) - integron , biology , salmonella enterica , genomic island , genetics , insertion sequence , microbiology and biotechnology , gene cassette , multiple drug resistance , transposable element , salmonella , prophage , tetracycline , chloramphenicol acetyltransferase , plasmid , genome , gene , escherichia coli , drug resistance , promoter , bacteriophage , bacteria , gene expression , antibiotics
Salmonella enterica serovar Typhimurium is frequently associated with life-threatening systemic infections, and the recent global emergence of multidrug resistance inS. enterica isolates from agricultural and clinical settings has raised concerns. In this study, we determined the whole-genome sequence of fluoroquinolone-resistantS. enterica serovar Typhimurium T000240 strain (DT12) isolated from human gastroenteritis in 2000. Comparative genome analysis revealed that T000240 displays high sequence similarity to strain LT2, which was originally isolated in 1940, indicating that progeny of LT2 might be reemerging. T000240 possesses a unique 82-kb genomic island, designated as GI-DT12, which is composed of multidrug resistance determinants, including a Tn2670 -like composite transposon (class 1 integron [intI1 ,blaoxa-30 ,aadA1 ,qacEΔ1 , andsul1 ], mercury resistance proteins, and chloramphenicol acetyltransferase), a Tn10 -like tetracycline resistance protein (tetA ), the aerobactin iron-acquisition siderophore system (lutA andlucABC ), and an iron transporter (sitABCD ). Since GI-DT12 is flanked by IS1 derivatives, IS1- mediated recombination likely played a role in the acquisition of this genomic island through horizontal gene transfer. The aminoglycoside-(3)-N -acetyltransferase (aac(3 )) gene and a class 1 integron harboring thedfrA1 gene cassette responsible for gentamicin and trimethoprim resistance, respectively, were identified on plasmid pSTMDT12_L and appeared to have been acquired through homologous recombination with IS26 . This study represents the first characterization of the unique genomic island GI-DT12 that appears to be associated with possible IS1 -mediated recombination inS. enterica serovar Typhimurium. It is expected that future whole-genome studies will aid in the characterization of the horizontal gene transfer events for the emergingS. enterica serovar Typhimurium strains.