Evaluation of the Meridian Premier EHEC assay as an indicator of Shiga toxin presence in direct faecal specimens.
Molecular testing for stx1 and/or stx2 is a reliable way of detecting Shiga toxigenic Escherichia coli (STEC) when faecal specimens can be cultured; however, detection of Shiga toxin in unculturable specimens is also of public health importance. The Meridian Premier EHEC assay was evaluated against the gold standard Vero cell cytotoxic assay for Shiga toxin detection in direct faecal specimens. An initial study of 817 patient specimens submitted for routine STEC detection was conducted, evaluating positive faeces detected by the Meridian assay with the Vero cell assay. Twenty-nine percent of 136 Meridian-positive faeces were confirmed as containing Shiga toxin. A further 62 faecal specimens were evaluated for statistical purposes, with all specimens tested by both Meridian and Vero cell assays. On direct faeces, the Meridian assay gave high specificity (76.95%) but low sensitivity (40%). This study confirmed that testing by Meridian assay on cultures is preferential to testing direct faeces for Shiga toxin.
Public Health Microbiology, Communicable Disease, Queensland Health Forensic and Scientific Services, Archerfield, Queensland 4108, Australia. megan_staples@health.qld.gov.au
Megan
M
Staples
Amy V
AV
Jennison
Rikki M A
RM
Graham
Helen V
HV
Smith
D000818:Animals; D001431:Bacteriological Techniques / Q000379:methods*; D018929:Cell Culture Techniques / Q000379:methods; D002522:Chlorocebus aethiops; D054324:Enterohemorrhagic Escherichia coli / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000175:diagnosis* / Q000382:microbiology; D005243:Feces / Q000382:microbiology*; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D022621:Shiga Toxin / Q000235:genetics*; D014709:Vero Cells
D022621:Shiga Toxin