Purpose: Selective media is formulated to promote growth of desired bacteria while inhibiting others. However, how effective is the media that is relied upon for isolation and identification of Vv and Vp? This study addresses the reliability of four common media used for isolation and identification of Vv and Vp.
Methods: Suspect Vv and Vp isolates from direct plating of oyster, water, and sediment were replica plated onto T1N3, TCBS, CPC+, VVA, and CHROMagar to determine colony morphology. Colonies from T1N3 plates were inoculated into APW in 96-deep well plates and identified using multiplex PCR.
Results: Of the 2,318 isolates tested, 1,069 were confirmed via PCR as Vv and 43 were confirmed as Vp. TCBS was used to isolate and identify possible Vv or Vp. Use of this media led to correct identification of 85.80% of isolates, with a false negative rate of 24.58%. CPC+ and VVA were used to isolate and identify possible Vv. Correct identification occurred using these media with 83.14% and 70.84% of isolates, with false negative rates of 17.33% and 18.51%, respectively. CHROMagar was used to isolate and identify Vv and Vp. Isolates were correctly identified with this media 81.38% and 7.58% of the time, with false negative rates of 15.68% and 0.90%, respectively.
Significance: The use of reliable media that produces fewer false negatives supports a more accurate risk estimate. Thus, correctly identifying pathogens from food and environmental samples is important for public safety.