Any isolate with the following features should be immediately referred to your LRN reference laboratory:
- Gram stain shows fat, gram-negative rods in single or short chains that may demonstrate bipolar staining
- Faster growth at 25oC
- Gray-white, translucent colonies on sheep blood agar (SBA) at 24 hours that turn slightly yellow and opaque at 48 hours
- Irregular colonies that have a "fried egg" and/or "hammered copper" appearance after 48–72 hours
- Catalase positive
- Oxidase negative
- Urea negative
- Indole negative
