Botulinum toxin
Mycobacterium immunogenum infection: case reportA 34-year-old woman developed Mycobacterium immunogenum infection following treatment with botulinum toxin for teeth grinding.The woman presented with an erythematous, tender nodule over her left mandible. Three and a half months prior, botulinum toxin [dosage not stated] had been injected into her masseters for teeth grinding. No other procedures had been performed in that region. Of note, she had no significant background medical history; she also had no history of immunosuppression therapy.The woman was initially treated with phenoxymethylpenicillin, followed by clindamycin. Physical examination following current presentation revealed an erythematous, tender, fluctuant nodule located at the site of the botulinum toxin injection on the left angle of her jaw. The lesion was then aspirated, and the fluid was sent for culture. Skin biopsy revealed mixed granulomatous inflammation in the dermis, involving foamy histiocytes, lymphocytes, as well as a smaller number of plasma cells and neutrophils. Staining with Ziehl-Neelson was found to be negative. In the mean time, Mycobacterium immunogenum, susceptible to amikacin, clarithromycin and linezolid, was isolated from the aspirate culture. Hence, she started receiving clarithromycin for 6 months, with complete resolution of the nodule. The Mycobacterium immunogenum infection was thought to have resulted from contamination of the botulinum toxin needles.