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Infectious Diseases

Training Level



Henry Ford Hospital


Introduction: Rapidly growing mycobacterium (RGM) skin and soft tissue infections are increasing in incidence. These infections can be challenging to treat and require multiple antibiotics for prolonged duration.This is a rare case of an immunocompetent male with Mycobacterium Septicum wound infection.Case presentation:52-year-old male with known history of hypertension and end-stage renal disease, was referred to Infectious disease (ID) clinic for multiple skin lesions.Initially noticed lesions near his right elbow and right foot which started as tender, erythematous papules and progressed to pustules with serosanguinous discharge over 2-weeks. He denied working with fish/aquarium, receiving pedicures or any trauma. Physical exam demonstrated draining lesions on his right dorsal foot and right elbow. Wound cultures were sent along with right foot shave biopsy for histopathology and cultures (bacterial, fungal and AFB). Pathology resultdemonstrated suppurative and granulomatous dermatitisandAFB cultures isolated M. septicum.He was started on oral azithromycin, levofloxacin, doxycycline and trimethoprim-sulfamethoxazole. Once antimicrobial susceptibilities were finalized, only levofloxacin Q48hrs and PO Bactrim DS BID Q48hrs were continued with improvement noted on subsequent follow up visits. Discussion: Mycobacterium septicum is an ubiquitous, rapidly growing, non-tuberculous mycobacterium (NTM) associated with a wide spectrum of clinical diseases in immunocompetent and immunosuppressed population. It was previously identified phenotypically as a member of the Mycobacterium fortuitum third-biovariant complex. Further analysis led to its recognition as a new species in 2000. Since then, only a handful of cases are reported and this is likely the second case of skin/soft tissue M. septicum infection.Management is based solely on clinical experiences. Since RGMs are notorious for resistant to anti-tuberculous drugs, treatment relies on accurate identification and drug-susceptibility testing. Commonly macrolide, quinolones and aminoglycosides are used for extended duration. For our patient, given the progression of skin lesions, we opted for a 4-drug regimen with quinolone, macrolide, tetracycline and trimethoprim-sulfamethoxazole with de-escalation based on final culture susceptibility for at least 6 months. Conclusion: Although rare, M. septicum can cause skin/soft tissue infections. Given the increasing incidence of NTM infections, exact speciation along with antimicrobial susceptibility testing, should be performed to avoid delays in diagnosis and treatment.

Presentation Date


Skin and Soft tissue infections - The New Kid on the Block