title: Validation of the ANSR Listeria method for detection of Listeria spp. in environmental samples.
abstract: ANSR Listeria is a new diagnostic assay for detection of Listeria spp. in sponge or swab samples taken from a variety of environmental surfaces. The method is an isothermal nucleic acid amplification assay based on the nicking enzyme amplification reaction technology. Following single-step sample enrichment for 16-24 h, the assay is completed in 40 min, requiring only simple instrumentation. In inclusivity testing, 48 of 51 Listeria strains tested positive, with only the three strains of L. grayi producing negative results. Further investigation showed that L. grayi is reactive in the ANSR assay, but its ability to grow under the selective enrichment conditions used in the method is variable. In exclusivity testing, 32 species of non-Listeria, Gram-positive bacteria all produced negative ANSR assay results. Performance of the ANSR method was compared to that of the U.S. Department of Agriculture-Food Safety and Inspection Service reference culture procedure for detection of Listeria spp. in sponge or swab samples taken from inoculated stainless steel, plastic, ceramic tile, sealed concrete, and rubber surfaces. Data were analyzed using Chi-square and probability of detection models. Only one surface, stainless steel, showed a significant difference in performance between the methods, with the ANSR method producing more positive results. Results of internal trials were supported by findings from independent laboratory testing. The ANSR Listeria method can be used as an accurate, rapid, and simple alternative to standard culture methods for detection of Listeria spp. in environmental samples.
authors.forename: Michael
authors.initials: M
authors.lastname: Wendorf
authors.forename: Emily
authors.initials: E
authors.lastname: Feldpausch
authors.forename: Lisa
authors.initials: L
authors.lastname: Pinkava
authors.forename: Karen
authors.initials: K
authors.lastname: Luplow
authors.forename: Edan
authors.initials: E
authors.lastname: Hosking
authors.forename: Paul
authors.initials: P
authors.lastname: Norton
authors.forename: Preetha
authors.initials: P
authors.lastname: Biswas
authors.forename: Mark
authors.initials: M
authors.lastname: Mozola
authors.forename: Jennifer
authors.initials: J
authors.lastname: Rice
mesh_terms: D000465:Algorithms; D001431:Bacteriological Techniques / Q000379:methods; D004783:Environmental Microbiology; D004784:Environmental Monitoring / Q000379:methods; D005516:Food Microbiology / Q000379:methods*; D008087:Listeria / Q000235:genetics / Q000378:metabolism*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D012984:Software; D013193:Stainless Steel; D013997:Time Factors
chemical_list: D011933:Reagent Kits, Diagnostic; D013193:Stainless Steel