A 52-year-old male with a 25-year smoking history had been living on the street for an unknown period of time. He sought medical attention because of overall poor health and was found to be anemic with weight loss. A spiculated mass was observed in his left middle lung lobe on chest film, and a lobectomy was performed with the possible diagnosis of carcinoma. The pathology department reported numerous necrotizing granulomas and chronic inflammation, but no carcinoma was observed in the lung tissue. Gram staining demonstrated “dark-staining gram-variable debris” but no definitive organisms. The patient had an uneventful recovery without antiinfective therapy. Routine bacterial and fungal cultures of the lung tissue were negative, but the broth mycobacterial culture grew a gram-negative rod. The rod only grew on charcoal yeast extract agar (CYE), but not on blood or chocolate agars. It was oxidase and urease positive, motile, and beta-lactamase positive. The catalase reaction was weak; nitrate was negative. It did not react with Legionella antiserum.

Questions

1. The significant characteristics of this bacterium include growth in broth and on CYE plates. Most laboratories typically do not have CYE available for routine culture. What would be the recommended procedure after isolation of a gram-negative rod from a normally sterile specimen with an original order for mycobacterium testing?

2. The isolate was identified as Afipia broomeae using DNA homology testing. According to Weyant21 et al. (1996), this bacterium is characterized for its growth on CYE and in broth, but not on other laboratory media. The species identification is based on a positive oxidase, catalase, urease, and xylose and a negative nitrate reduction. A. felis is identical except it is nitrate positive. Although the CDC collection of A. felis is mostly from lymph nodes, most of the A. broomeae were from respiratory specimens. What is the likely route of transmission, or how was the individual exposed to the organism resulting in the infection?

3. Because both Afipia and Bartonella are difficult to grow, should the laboratory attempt to provide culture services?