title: Pathogen Inactivating Properties and Increased Sensitivity in Molecular Diagnostics by PAXgene, a Novel Non-Crosslinking Tissue Fixative.
abstract: BACKGROUND
  Requirements on tissue fixatives are getting more demanding as molecular analysis becomes increasingly relevant for routine diagnostics. Buffered formaldehyde in pathology laboratories for tissue fixation is known to cause chemical modifications of biomolecules which affect molecular testing. A novel non-crosslinking tissue preservation technology, PAXgene Tissue (PAXgene), was developed to preserve the integrity of nucleic acids in a comparable way to cryopreservation and also to preserve morphological features comparable to those of formalin fixed samples.
  
  
  METHODS
  Because of the excellent preservation of biomolecules by PAXgene we investigated its pathogen inactivation ability and biosafety in comparison to formalin by in-vitro testing of bacteria, human relevant fungi and human cytomegalovirus (CMV). Guidelines for testing disinfectants served as reference for inactivation assays. Furthermore, we tested the properties of PAXgene for detection of pathogens by PCR based assays.
  
  
  RESULTS
  All microorganisms tested were similarly inactivated by PAXgene and formalin except Clostridium sporogenes, which remained viable in seven out of ten assays after PAXgene treatment and in three out of ten assays after formalin fixation. The findings suggest that similar biosafety measures can be applied for PAXgene and formalin fixed samples. Detection of pathogens in PCR-based diagnostics using two CMV assays resulted in a reduction of four to ten quantification cycles of PAXgene treated samples which is a remarkable increase of sensitivity.
  
  
  CONCLUSIONS
  PAXgene fixation might be superior to formalin fixation when molecular diagnostics and highly sensitive detection of pathogens is required in parallel to morphology assessment.
authors.affiliation: Christian Doppler Laboratory for Biospecimen Research and Biobanking Technologies, Institute of Pathology, Medical University Graz, Graz, Austria.|Medical University Graz, Institute of Pathology, Graz, Austria.
authors.forename: Martina
authors.initials: M
authors.lastname: Loibner
authors.affiliation: Medical University Graz, Institute of Hygiene, Microbiology and Environmental Medicine, Graz, Austria.
authors.forename: Walter
authors.initials: W
authors.lastname: Buzina
authors.affiliation: Medical University Graz, Institute of Pathology, Graz, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Viertler
authors.affiliation: Qiagen GmbH, Research and Development, Hilden, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Groelz
authors.affiliation: Christian Doppler Laboratory for Biospecimen Research and Biobanking Technologies, Institute of Pathology, Medical University Graz, Graz, Austria.|LKH Hospital Weiz, Laboratory of Medical Department, Weiz, Austria.
authors.forename: Anja
authors.initials: A
authors.lastname: Hausleitner
authors.affiliation: Christian Doppler Laboratory for Biospecimen Research and Biobanking Technologies, Institute of Pathology, Medical University Graz, Graz, Austria.|Medical University Graz, Institute of Pathology, Graz, Austria.
authors.forename: Gintare
authors.initials: G
authors.lastname: Siaulyte
authors.affiliation: Christian Doppler Laboratory for Biospecimen Research and Biobanking Technologies, Institute of Pathology, Medical University Graz, Graz, Austria.|Medical University Graz, Institute of Pathology, Graz, Austria.
authors.forename: Iris
authors.initials: I
authors.lastname: Kufferath
authors.affiliation: Medical University Graz, Institute of Hygiene, Microbiology and Environmental Medicine, Graz, Austria.
authors.forename: Bettina
authors.initials: B
authors.lastname: Kölli
authors.affiliation: Christian Doppler Laboratory for Biospecimen Research and Biobanking Technologies, Institute of Pathology, Medical University Graz, Graz, Austria.|Medical University Graz, Institute of Pathology, Graz, Austria.
authors.forename: Kurt
authors.initials: K
authors.lastname: Zatloukal
mesh_terms: D001419:Bacteria / Q000235:genetics; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D003587:Cytomegalovirus / Q000187:drug effects; D005404:Fixatives / Q000494:pharmacology*; D005557:Formaldehyde / Q000494:pharmacology; D005658:Fungi / Q000235:genetics; D006801:Humans; D050296:Microbial Viability; D057089:Pathology, Molecular; D060888:Real-Time Polymerase Chain Reaction; D016707:Tissue Fixation / Q000379:methods*; D038301:Virus Inactivation / Q000187:drug effects
chemical_list: D003432:Cross-Linking Reagents; D005404:Fixatives; D005557:Formaldehyde