After extending incubation period for cultures, non-tuberculous mycobacteria cutaneous infection was found on woman injecting insulin through clothing….
L.S., a 47 year old, type 1 diabetic who had been injecting herself at various locations through her clothing since adolescence, presented to the infectious disease physician after suffering from a painful, nonhealing skin lesion. The patient denied a history preceding trauma, foreign travel, exposure to aquatic animals, or exposure to hot tubs. She had unsuccessfully been treated by her primary care physician with several courses of oral antibiotics, including: cephalexin, clindamycin, and amoxicillin.
Histology of the biopsied lesion presented nonspecific inflammation with negative stains for acid-fast bacilli and fungi. Cultures were positive for mycobacteria spp. after an extended incubation period of 63 days was performed, compared to the conventional 49 days. Mycobacterium immunogenum was identified following a 16S rRNA sequencing process. The organism was susceptible to clarithromycin and tigecycline, and demonstrated intermediate sensitivity to amikacin.
Non-tuberculous mycobacteria are widely distributed throughout the environment. Human infection is more likely to originate from an unidentified environmental source, as opposed to human-to-human transmission.
Rabia A. Ahmed and colleague, from the University of Alberta in Edmonton, Canada writes, "We speculate that the practice of injecting insulin through clothing may have been a contributing factor to infection in our patient because it is possible that the organism was present on her clothing with subsequent injection into skin." L.S. did report having been instructed to inject insulin through her clothes. The researchers behind this study claim, "Insulin injections have been associated with non-tuberculous mycobacteria cutaneous infections, and injection techniques should be reviewed with patients to prevent these infections."
Clinical Diabetes April 2013 vol. 31 no. 2 76-78 doi: 10.2337/diaclin.31.2.76