Chancroid lesion stained with gentian violet
PHIL CDC
Gram stain of clinical specimens may show characteristic chains of gram negative rods--"schools of red fish"
Culture ulcer lesion material and/or bubo aspirates
Culture only about 80% sensitive
- Inoculate at the bedside onto 2 media:
Gonococcal agar supplemented with 2% bovine hemoglobin and 5% fetal calf serum, 1% IsovitaleX supplement
Mueller-Hinton agar supplemented with 5% chocolatized horse blood, 1% Isovitalex supplement and 3 µ/mL of vancomycin
Culture Incubation: 5% CO2 in a humid environment at 33°C to 35°C (critical that the temperature does not exceed 35°C)
Culture very difficult
Labs seldom have media on hand
Organism dies rapidly outside the body
No commercially available FDA-approved tests for antigen detection, serology or NAAT
Gram stain of colonies shows gram negative coccobacilli
Produces characteristic yellowish tan colonies: very adherent and can be pushed intact over the agar surface
Oxidase positive
Requires X factor