title: False-positive results after environmental pinworm PCR testing due to Rhabditid nematodes in Corncob bedding.
abstract: Modern rodent colonies are housed in individually ventilated cages to protect the animals from contamination with adventitious pathogens. Standard health monitoring through soiled-bedding sentinels does not always detect infections, especially in the context of low pathogen prevalence. Recently proposed alternatives include analyzing environmental samples from the cages or rack exhaust by PCR to improve the detection of rodent pathogens but optimal sampling strategies have not yet been established for different microorganisms. Although generally very sensitive and specific, these molecular assays are not foolproof and subject to false-positive and -negative results and should always be interpreted cautiously with an overall understanding of the intrinsic controls and all the variables that may affect the results. Here, we report a limited Aspiculuris tetraptera outbreak in a mouse barrier facility that was detected by fecal PCR in sentinels and confirmed by fecal flotation and direct cecal examination of both sentinels and colony animals. The outbreak led to a widespread survey of all facilities for pinworms by using environmental PCR from ventilated rack exhaust plenums. Environmental PCR suggested an unexpected widespread contamination of all ventilated racks holding nonautoclaved cages, but results could not be confirmed in sentinel or colony animals by fecal flotation, cecal and colonic examination, or cage PCR testing. After additional investigation, the unexpected environmental PCR results were confirmed as false-positive findings due to the nonspecificity of the assay, leading to the amplification of rhabditid nematodes, which are not infectious in rodents but which contaminated the corncob bedding.
authors: Animal Resources Department, The Salk Institute, for Biological Studies, La Jolla, California, USA.
authors: Mathias
authors: M
authors: Leblanc
authors: Animal Resources Department, The Salk Institute, for Biological Studies, La Jolla, California, USA.
authors: Kristina
authors: K
authors: Berry
authors: Animal Resources Department, The Salk Institute, for Biological Studies, La Jolla, California, USA.
authors: Sandy
authors: S
authors: Graciano
authors: Animal Resources Department, The Salk Institute, for Biological Studies, La Jolla, California, USA.
authors: Brandon
authors: B
authors: Becker
authors: Animal Resources Department, The Salk Institute, for Biological Studies, La Jolla, California, USA. reuter@salk.edu.
authors: Jon D
authors: JD
authors: Reuter
mesh_terms: D000818:Animals; D001512:Bedding and Linens; D004757:Enterobius; D005243:Feces; D006799:Housing, Animal; D051379:Mice; D010123:Oxyuriasis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D010124:Oxyuroidea / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D012376:Rodent Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000469:parasitology*
references: Endocrinology. 2012 Feb;153(2):949-53
references: 22186416
references: J Am Assoc Lab Anim Sci. 2008 Nov;47(6):61-6
references: 19049256
references: J Am Assoc Lab Anim Sci. 2009 Jul;48(4):378-80
references: 19653945
references: Exp Parasitol. 1976 Feb;39(1):40-4
references: 943307
references: Clin Microbiol Rev. 1998 Apr;11(2):231-66
references: 9564563
references: Clin Microbiol Rev. 2004 Oct;17(4):840-62, table of contents
references: 15489351
references: Am J Hyg. 1952 Nov;56(3):287-93
references: 12996496
references: Lab Anim Sci. 1994 Oct;44(5):517-20
references: 7844964
references: J Am Assoc Lab Anim Sci. 2012 Mar;51(2):162-9
references: 22776115
references: PLoS One. 2012;7(3):e33973
references: 22479490
references: Contemp Top Lab Anim Sci. 1999 Jan;38(1):64-66
references: 12086454
references: Contemp Top Lab Anim Sci. 2000 May;39(3):8
references: 11178317
references: Appl Environ Microbiol. 1995 Jun;61(6):2297-301
references: 7793950
references: Comp Med. 2004 Aug;54(4):382-92
references: 15357318
references: J Am Assoc Lab Anim Sci. 2013 Jan;52(1):28-33
references: 23562030
references: Lab Anim. 2004 Jan;38(1):11-6
references: 14979983
references: Lab Anim Sci. 1994 Feb;44(1):73-5
references: 8007667
references: Contemp Top Lab Anim Sci. 1996 Mar;35(2):69-70
references: 16457515
references: Int J Syst Bacteriol. 1995 Jul;45(3):595-9
references: 8590690
references: Trends Genet. 2009 May;25(5):203-9
references: 19361881
references: ILAR J. 2008;49(3):316-25
references: 18506065
references: Lab Anim. 2006 Jul;40(3):247-60
references: 16803642
references: J Am Assoc Lab Anim Sci. 2011 Nov;50(6):904-9
references: 22330785
references: J Nematol. 2001;33(1):1-70
references: 19265873
references: J Am Assoc Lab Anim Sci. 2009 May;48(3):263-7
references: 19476714
references: J Am Assoc Lab Anim Sci. 2010 Mar;49(2):184-9
references: 20353693
references: Lab Anim Sci. 1990 Jul;40(4):367-70
references: 2166862
references: PCR Methods Appl. 1993 Dec;3(3):S30-7
references: 8118394