Purpose: This PT study includes data from three test events in 2013, where 128 participants submitted results for detection and identification of an unknown STEC. Our objective was to assess whether laboratories can properly detect and identify STEC adulterants.
Methods: Responses for the seven STECs were recorded from 254 cumulative proficiency testing results submitted in three test events in the year 2013. Participants were allowed to test the PT sample using the method of their choice and were asked to report the method used.
Results: Laboratories accurately detected an STEC present in a sample 96.1% of the time. When the laboratory attempted to identify the strain, 95.6% of identifications were correct. However, 39.9% of responses indicated participants were unable to, or chose not to, identify the strain in a particular sample.
Significance: As laboratories gain experience in routine testing for these STEC adulterants, proficiency testing will be useful in assessing their ability to detect and identify STECs. The current results indicate that a significant portion of laboratories may test for the presence of STECs without identifying the strain. This may change as industry practices and laboratory test methods for identifying these strains continue to evolve.