Phylogenetic group distribution and prevalence of virulence genes in Escherichia coli isolates from food samples in South Korea.
We analyzed the distribution of phylogenetic groups of foodborne Escherichia coli isolates. We also investigated the prevalence of virulence-associated genes of diarrheagenic E. coli. In total, 162 E. coli isolated from foods (raw meat, fish, and processed foods) were collected in Korea. Approximately 90% of the foodborne isolates belonged to phylogenetic groups A and B1, whereas 1.2% were allocated to group B2, and 9.3% to D. Multiplex polymerase chain reaction (PCR) assays were used to detect the following: stx (1) and stx (2) to identify Shiga toxin-producing E. coli (STEC), eae and bfpA to identify enteropathogenic E. coli (EPEC), ipaH for enteroinvasive E. coli, CVD432 for enteroaggregative E. coli, and lt and st for enterotoxigenic E. coli (ETEC). The presence of daaD in diffusely adherent E. coli was examined by singleplex PCR. Of the 162 foodborne E. coli isolates, three (1.9%) were confirmed to be pathogenic E. coli: STEC, ETEC, and atypical EPEC based on their possession of stx (1), st, and eae, and the pathogenic strains were isolated in beef, rockfish, and pork, respectively. Molecular typing was conducted by multilocus sequence typing to investigate the genetic relationships among the pathogenic strains. All isolates positive for virulence genes had different mulilocus sequence typing profiles representing different sequence types (ST) of ST101, ST1815, and ST1820. These results indicate that some food samples were contaminated with pathogenic E. coli.
Department of Food Bioscience and Technology, Laboratory of Food Safety and Evaluation, College of Life Sciences and Biotechnology, Korea University, Anam-dong, Seongbuk-gu, Seoul, 136-713, Korea.
Hyon-Ji
HJ
Koo
Hyo-Sun
HS
Kwak
Sang-Hyeon
SH
Yoon
Gun-Jo
GJ
Woo
D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D029968:Escherichia coli Proteins / Q000235:genetics*; D005516:Food Microbiology; D005838:Genotype; D007723:Korea; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D056910:Republic of Korea; D037521:Virulence Factors / Q000235:genetics*
D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D037521:Virulence Factors