Comparative sequence analysis of enteroaggregative Escherichia coli heat-stable enterotoxin 1 identified in Korean and Japanese Escherichia coli strains

• Published in: International journal of food microbiology 2017-02, Vol.243, p.1-8
• Main Authors: Seo, Dong Joo, Choi, SunKeum, Jeon, Su Been, Jeong, Suntak, Park, Hyunkyung, Lee, Bog-Hieu, Kim, Geun-Bae, Yang, Soo-Jin, Nishikawa, Yoshikazu, Choi, Changsun
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Animals; astA; Base Sequence; Cattle; Cloning; Comparative analysis; Deoxyribonucleic acid; Diarrhea; DNA; E coli; Electrophoresis, Gel, Pulsed-Field; Enteroaggregative Escherichia coli heat-stable enterotoxin 1 (EAST1); Enterotoxigenic Escherichia coli - genetics; Enterotoxigenic Escherichia coli - isolation & purification; Enterotoxigenic Escherichia coli - pathogenicity; Enterotoxin A; Enterotoxins - genetics; Escherichia coli; Escherichia coli Infections - microbiology; Escherichia coli Proteins - genetics; Feces - microbiology; Gel electrophoresis; Genes; Hot Temperature; Humans; Japan; Meat - microbiology; Nucleotide sequence; Outbreaks; Plasmids; Polymerase Chain Reaction; Pulse field gel-electrophoresis (PFGE); Republic of Korea; Sequence Analysis, DNA; Sequencing; Swine - microbiology; Swine Diseases - microbiology; Thermal stability; Virulence; Virulence - genetics
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2016.11.017

The aim of this study was to compare the sequence of the astA gene found in 8 Korean and 11 Japanese Escherichia coli isolates. Conventional PCR was used to amplify the astA gene from the chromosomal and plasmid DNA preparation samples of each isolate using commercial DNA extraction kits. Cloning of the PCR products, sequence analysis, and pulse field gel electrophoresis (PFGE) were sequentially performed. An identical copy of astA in each isolate were found for 8 Korean and 8 Japanese E. coli strains isolated from bovine, porcine, and healthy human carriers. Among these, 1 Korean and 4 Japanese isolates carried a stop mutation at residue 16. Three Japanese outbreak strains (V199, V638, and 96-127-23) carried multiple clones of astA gene with multiple amino acids changes at residues 11, 16, 20, 23, 30, 33, and 34. Compared with the non-diarrheal isolates, clonal diversity and sequence variations of the astA gene in outbreak isolates may be associated with virulence potential of EAST1. •Sequence of astA gene in Korean and Japanese E. coli isolates was compared.•All astA-positive E. coli isolates were negative for other virulence factors.•Bovine, porcine, and healthy human carrier isolates carried the identical astA.•Polymorphisms of multiple clonal astA in E. coli outbreak isolates were found.