title: Promising Nucleic Acid Lateral Flow Assay Plus PCR for Shiga Toxin-Producing Escherichia coli.
abstract: Shiga toxin (Stx)-producing Escherichia coli (STEC) is a frequent cause of foodborne infections, and methods for rapid and reliable detection of STEC are needed. A nucleic acid lateral flow assay (NALFA) plus PCR was evaluated for detecting STEC after enrichment. When cell suspensions of 45 STEC strains, 14 non-STEC strains, and 13 non-E. coli strains were tested with the NALFA plus PCR, all of the STEC strains yielded positive results, and all of the non-STEC and non-E. coli strains yielded negative results. The lower detection limit for the STEC strains ranged from 0.1 to 1 pg of genomic DNA (about 20 to 200 CFU) per test, and the NALFA plus PCR was able to detect Stx1- and Stx2-producing E. coli strains with similar sensitivities. The ability of the NALFA plus PCR to detect STEC in enrichment cultures of radish sprouts, tomato, raw ground beef, and beef liver inoculated with 10-fold serially diluted STEC cultures was comparable to that of a real-time PCR assay (at a level of 100 to 100,000 CFU/ml in enrichment culture). The bacterial inoculation test in raw ground beef revealed that the lower detection limit of the NALFA plus PCR was also comparable to that obtained with a real-time PCR assay that followed the U.S. Department of Agriculture guidelines. Although further evaluation is required, these results suggest that the NALFA plus PCR is a specific and sensitive method for detecting STEC in a food manufacturing plant.
authors.affiliation: R&D Center, NH Foods Ltd., 3-3 Midorigahara, Tsukuba, Ibaraki 300-2646, Japan. y.terao@nipponham.co.jp.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Terao
authors.affiliation: R&D Center, NH Foods Ltd., 3-3 Midorigahara, Tsukuba, Ibaraki 300-2646, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Takeshita
authors.affiliation: R&D Center, NH Foods Ltd., 3-3 Midorigahara, Tsukuba, Ibaraki 300-2646, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Nishiyama
authors.affiliation: R&D Center, NH Foods Ltd., 3-3 Midorigahara, Tsukuba, Ibaraki 300-2646, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Morishita
authors.affiliation: R&D Center, NH Foods Ltd., 3-3 Midorigahara, Tsukuba, Ibaraki 300-2646, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: R&D Center, NH Foods Ltd., 3-3 Midorigahara, Tsukuba, Ibaraki 300-2646, Japan.
authors.forename: Fumiki
authors.initials: F
authors.lastname: Morimatsu
mesh_terms: D000818:Animals; D002417:Cattle; D017931:DNA Primers / Q000235:genetics; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D017408:Guidelines as Topic; D057230:Limit of Detection; D018551:Solanum lycopersicum / Q000382:microbiology; D031224:Raphanus / Q000382:microbiology; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D000069466:Red Meat / Q000382:microbiology; D036226:Seedlings / Q000382:microbiology; D012680:Sensitivity and Specificity; D054323:Shiga-Toxigenic Escherichia coli / Q000235:genetics / Q000302:isolation & purification*; D014481:United States; D016885:United States Department of Agriculture
chemical_list: D017931:DNA Primers