title: Potential rapid and simple lateral flow assay for Escherichia coli O111.
abstract: We developed and evaluated a lateral flow assay (LFA) as a simple and rapid method for direct detection of Escherichia coli O111 in food after enrichment. When cell suspensions of 8 E. coli O111 strains and 77 non-E. coli O111 strains were tested with the LFA, the former all yielded positive results and the latter all yielded negative results. The minimum detection limits for the E. coli O111 strains were 1.8 × 10(3) to 5.6 × 10(5) CFU/ml of cell suspension, and the LFA was able to detect live cultures or those killed by autoclaving at nearly the same level of sensitivity. To evaluate the ability of LFA to detect its target in food, enrichment cultures of meat samples inoculated with 10-fold serial dilutions of E. coli O111 were tested with the LFA and PCR. Even when there were very few E. coli O111 cells in the meat samples (1.6 × 10(0) to 1.6 × 10(1) CFU/25 g of food), when they were cultured in modified E. coli broth with novobiocin for 22 h at 42°C, the LFA yielded positive results that corresponded to the PCR results. Although the LFA requires further evaluation and field study, these results suggest that this assay has sufficient sensitivity and specificity. This procedure can be completed with a one-step incubation after the test strip has been inserted into the sample after 22 h of culture, whereas the standard culture method requires multiple cultures, skilled personnel, a well-equipped laboratory, and 4 or 5 days. The speed and simplicity of this LFA make it suitable for use as part of routine screening assays in the food industry.
authors: R&D Center, Nippon Meat Packers, Inc., 3-3 Midorigahara, Tsukuba, Ibaraki 300-2646, Japan. y.terao@nipponham.co.jp
authors: Yoshitaka
authors: Y
authors: Terao
authors: Taro
authors: T
authors: Yonekita
authors: Naoki
authors: N
authors: Morishita
authors: Tatsuya
authors: T
authors: Fujimura
authors: Takashi
authors: T
authors: Matsumoto
authors: Fumiki
authors: F
authors: Morimatsu
mesh_terms: D015169:Colony Count, Microbial / Q000379:methods* / Q000592:standards*; D003470:Culture Media; D004269:DNA, Bacterial / Q000032:analysis; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D016133:Polymerase Chain Reaction; D011934:Reagent Strips; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D054323:Shiga-Toxigenic Escherichia coli / Q000302:isolation & purification*; D013997:Time Factors
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D011934:Reagent Strips