[Comparing traditional and commercial molecular biology detection of gastrointestinal pathogens with AusDiagnostics panels in Motol University Hospital].

Background: The aim was to do an internal audit of gastrointestinal pathogen detection at the Department of Medical Microbiology, Motol University Hospital between the years 2014 and 2018 and to test two commercial multiplex molecular biology assays potentially improving the diagnostic process and reducing costs.

Material and methods: Based on data from a laboratory information system (LIS), a total of 45,888 samples were identified which had been tested for the presence of gastrointestinal pathogens using culture, immunochromatographic, microscopic and molecular biology techniques between 2014-2018. Novel multiplex molecular biology detection was used to test 182 nucleic acid isolates obtained from stool samples with the Enteric Viruses (8-well) assay (Viral Panel, EVP) or Faecal Pathogens M (16-well) assay (Microbial Panel, FPM) manufactured by AusDiagnostics.

Results: The LIS data showed 6.2 % of positive pathogens causing diarrhea from all tested samples (detection rates: 4.5 % for bacterial agents, 21.6 % for viral agents and 0.4 % for parasitic agents). Valid samples (98.9 % of all tested samples) tested by the molecular biology technique yielded, in descending order: C. difficile toxin B (19 %), norovirus (9 %), astrovirus (8 %), Campylobacter (7 %), sapovirus (6 %), Yersinia enterocolitica (6 %), rotavirus (4 %), enterovirus (3 %), Aeromonas (3 %), adenovirus (2 %) and Salmonella (1 %). There was found at least 1 additional new positive detection in 27 % of stools tested by the Viral Panel and in 40 % of stools tested by the Microbial Panel in comparison with the traditional approach. Introducing the panels into routine diagnostic practice will not reduce the costs.

Conclusions: The introduction of novel multiplex molecular biology assays for detecting gastrointestinal pathogens will considerably increase pathogen detection rates even though the costs will be higher for the Department of Medical Microbiology.