A 60-year-old female without any notable past medical or surgical history presented with redness, swelling, and pain at the base of her left fourth finger. Twelve hours before, she had cut the end of her finger with the tip of a pitchfork while mixing the compost in her garden. At the time of evaluation, the patient was afebrile and had no other symptoms. Due to suspicion of acute flexor phlegmon, surgical examination and trimming of the wound were performed. A purulent liquid was found in the flexor sheath and sent to the laboratory for bacteriological analysis, and the synovial sheath was washed. The wound was left open and covered with an Adaptic dressing. The patient was sent home with empirical antimicrobial therapy consisting of a standard dosage of amoxicillin-clavulanic acid treatment (three 1-g doses every 24 h for 7 days) and scheduled for a follow-up 48 h later. At the 48-h follow-up, the symptoms had resolved and the treatment was continued.
The anaerobic cultures were negative. In contrast, after 48 h of aerobic incubation, Columbia blood agar (35°C) and chocolate agar (35°C in 5% CO2) both yielded growth of a pure culture of grayish white, heterogeneously sized, and in some cases wrinkled colonies with an earthy odor. After conventional Gram staining, microscopic examination of the colonies revealed the structures seen in Fig. 1A and B. Partial acid-fast staining was negative. Examination of the plates after 72 h showed the appearance of powdery aerial hyphae (Fig. 1C) and a hazy zone of beta-hemolysis around the colonies on blood agar (Fig. 1D).
FIG 1.
(A and B) Gram stains of the unknown organism from a colony picked on chocolate agar (magnification, ×1,000). (C and D) Colony characteristics of the isolate on chocolate agar and Columbia blood agar.
For answer and discussion, see page 1228 in this issue (https://doi.org/10.1128/JCM.01397-15).