Any isolate with the following features should be immediately referred to your LRN reference laboratory:
B. mallei:
- Gram stain that reveals pale staining straight or slightly curved gram-negative coccobacilli
- Cells arranged in end-to-end pairs, parallel bundles, or Chinese letter form
- Smooth, gray, translucent colonies on sheep blood agar (SBA) at 48 hours
- Catalase positive
- Oxidase variable
- Indole negative
- Non-motile
B. pseudomallei:
- Gram stain shows slender gram-negative rods with bipolar staining
- Smooth form appears in Gram stain as long parallel bundles
- Rough form appears in Gram stain in an irregular arrangement
- Smooth, creamy, white colonies on SBA at 24 hours
- Dry, wrinkled colonies at 48–72 hours
- Catalase positive
- Oxidase positive
- Indole negative
- Motility positive
