Multiplex real-time PCR detection of heat-labile and heat-stable toxin genes in enterotoxigenic Escherichia coli.
A multiplex real-time PCR method was developed for detection of heat-labile and heat-stable toxin genes in enterotoxigenic Escherichia coli. Approximately 10 CFU per reaction mixture could be detected in rinsates from produce samples. Several foods representative of varieties previously shown to have caused enterotoxigenic E. coli outbreaks were spiked and enriched for 4 or 6 h. Both heat-labile and heat-stable toxin genes could be detected in the foods tested, with the exception of hot sauce, with threshold cycle values ranging from 25.2 to 41.1. A procedure using membrane filtration which would allow enumeration of the enterotoxigenic E. coli population in a food sample in less than 28 h by real-time PCR analysis of colonies picked from media highly selective for E. coli was also developed.
Pacific Regional Laboratory Northwest, US Food and Drug Administration, Bothell, Washington 98021, USA. mike.grant@fda.gov
Michael A
MA
Grant
Jinxin
J
Hu
Karen C
KC
Jinneman
D000595:Amino Acid Sequence; D000818:Animals; D001427:Bacterial Toxins / Q000235:genetics*; D015169:Colony Count, Microbial; D017931:DNA Primers; D004768:Enterotoxins / Q000235:genetics*; D004926:Escherichia coli / Q000302:isolation & purification*; D029968:Escherichia coli Proteins; D005506:Food Contamination / Q000032:analysis*; D006358:Hot Temperature; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods*
D001427:Bacterial Toxins; D017931:DNA Primers; D004768:Enterotoxins; D029968:Escherichia coli Proteins; C034151:heat stable toxin (E coli)