A small, gram-negative coccobacillus is isolated from a lymp…
A small, gram-negative coccobacillus is isolated from a lymph node aspirate of a hunter with ulceroglandular symptoms after handling wild rabbits. The organism grows poorly on standard media, but appears after 48 hours on cysteine-enriched chocolate agar. The organism is oxidase negative and provides a weak postive catalase reaction. The technologist presumptively identifies the isolate as Francisella tularensis. What is the next best step?