Case #11:

Clinical Presentation:
A 25-year-old restaurant worker presented with nodular skin lesions on his hand (Case 11 Image 1). The lesions developed in an ascending proximal fashion. Several months previously, he had sustained a puncture (splinter) injury from wood to his hand. At home, he maintained a fish tank which he cleaned on a regular basis. He had undergone multiple bacteriologic and mycologic studies in an attempt to establish a diagnosis.

Clinical Diagnoses:
Sporotrichosis
Mycobacterium marinum soft-tissue infection

Case 11 Image 2: Ziehl-Neelsen stain of lesion scrapings showing acid-fast beaded bacilli.
Case 11 Image 3: culture of lesion aspirate on Lowenstein-Jensen medium, incubated at 30¡C, showing light-induced (photochromogenic) yellow pigmented colonies.
Case 11 Image 4: Ziehl-Neelsen stain of water from the patient's fish tank showing numerous acid-fast bacilli.

Discussion:
Microbiologic Diagnosis:
Mycobacterium marinum
This organism is present in fresh and salt water and can contaminate open wounds. Aquarium exposure and fish or shellfish associated injuries account for the majority of infections.