A 37-year-old man was admitted to a local hospital complainingof a severe headache of several days, moderate fever, chest pain,and a productive cough. Swollen lymph nodes and a tender, enlargedliver were also noted. He is a professional furrier and trapper andhad recently returned from an excursion on which he had trapped andskinned approximately 30 rabbits.
Routinesputum and blood cultures were collected and inoculated aerobicallyand anaerobically onto routine media (blood agar plate, MacConkeyagar, and CA, and MAC). Although Gram stains of both the blood andsputum seemed to demonstrate the presence of very faintly staininggram-negative coccobacilli, no growth was obtained on any of thecultures after 72 hours.
After6 days, the chocolate agar plates from the blood culture began togrow tiny transparent colonies of the organism. These colonies wereoxidase negative and weakly catalase positive. Unable toconclusively identify the organism using any of their routinemethods, the laboratory sent the isolate to a referencelaboratory.
Whileawaiting the final identification results from the referencelaboratory, the patient’s pneumonia condition worsened, complicatedby liver failure, and he died 3 weeks following admission.
Question:
-Why did the organism only grow on chocolate agar? Name twoother types of media on which the organism will grow well.
