A 56 year old woman with no significant past medical history sustained a minor puncture wound to her thumb while opening a wine bottle with a cork screw. Two weeks later the thumb developed redness and swelling. She visited her primary care physician, who prescribed a ten-day course of amoxicillin. The swelling and redness spread to her fingers and wrist, and she subsequently developed extensor tenosynovitis. The wound was debrided and cultures were sent to the clinical microbiology lab.

After two weeks, growth was seen on a Lowenstein Jensen slant that was incubated at 30°C. A Kinyoun stain of the organism (Figure 1) and colony morphology on 7H11 agar (Figure 2) are shown. No growth was observed in cultures incubated at 35°C. 






What is the most likely source of this patient’s wound infection?