Mycobacterium immunogenum

Wilson RW et al (2001)

M. immunogenum is a nontuberculous mycobacterium first described in 2001 by Wilson et al. as a fast-growing variety and a new species in the Mycobacterium chelonae-Mycobacterium abscessus group. PCR restriction analysis of a 439-bp segment of the hsp65 gene and/or sequencing of the species-specific region of 16S rDNA may confirm this new species.

Mycobacterium immunogenum was first described in 2001. To date, only a few cases have been published, all in the Americas. Since the initial description of M. immunogenum, <10 clinical case reports have been published, most of which involved cutaneous infections and all of which occurred in the Americas. Individual cases have since been detected in Europe.

Outbreaks of M. immunogenum have been described in association with cosmetic procedures and nosocomial transmission. Although only a few cases have been published to date, the infections are apparently not uncommon (Garcia-Zamora E et al. 2017).

More than 50% of patients had persistent red papules, nodules, or plaques that progressed despite treatment with topical corticosteroids and several systemic antibiotic cycles. Usually, the skin lesions are not complicated by fever or chills or other general malaise.

In disseminated M. immunogenum infections in immunodepressed individuals, the skin lesions may be complicated by septic shock (Garcia-Zamora E et al. 2017).

In most cases, the infection resulted from an invasive procedure performed weeks or months earlier, such as after mesotherapy or tattoos.

Clarithromycin plus levofloxacin or ciprofloxacin or amikacin over a period of approximately 6 months.

Case Report: A 65-year-old woman presented with a 3-month history of pruritic lesions on the abdomen. Examination revealed erythematous inflammatory papules, pustules, and crusts. Three weeks later, mycobacteria were cultured from the biopsy specimen. Based on the results of the susceptibility test and restriction enzyme analysis by polymerase chain reaction (PCR), Mycobacterium immunogenum was identified. Treatment with clarithromycin plus levofloxacin was initiated.

1. Garcia-Zamora E et al. (2017) Cutaneous infection due to Mycobacterium immunogenum: an European case report and review of the literature. Dermatol Online J 23:13030/qt9zg5r07t.
2. Gonzalez-Santiago TM et al (2015) Nontuberculous Mycobacteria: skin and soft tissue infections. Dermatol Clin 33:563-577.
3. Loots MA et al (2005) Chronic leg ulcer caused by Mycobacterium immunogenum. J Travel Med 12: 347-349.
4. Shedd AD et al (2010) Mycobacterium immunogenum skin infections: two different presentations. Int J Dermatol 49: 941-944.
5. Wallace RJ Jr et al (2002) Presence of a single genotype of the newly described specie Mycobacterium immunogenum in industrial metalworking fluids associated with hypersensitivity pneumonitis. Appl Environ Microbiol 68:5580-5584.
6. Wilson RW et al. (2001) Mycobacterium immunogenum sp. nov, a novel species related to Mycobacterium abscessus and associated with clinical disease, pseudo-outbreaks and contaminated metalworking fluids: an international cooperative study on mycobacterial taxonomy. Int J Syst Evol Microbiol 51 (Pt 5): 1751-1764.