Disseminated Mycobacterium simiae infection in a non-immunosuppressed patient in the USA

Mycobacterium simiae: Harmless colonizer or deadly pathogen?

“…simiae was initially considered as an environmental pathogen and is rarely associated with human illness [4]. More recently, M. simiae has been described to cause a spectrum of clinical syndromes, ranging from an asymptomatic infection to a fatal disseminated disease [5,18,19].…”

“…M. simiae mostly causes pulmonary disease [5]. Immunocompetent patients usually develop respiratory infections in the setting of underlying lung diseases such as cystic fibrosis and chronic obstructive pulmonary disease, smoking, or a history of pulmonary tuberculosis [20].…”

“…simiae can also cause various focal infections [20]. Cases of osteomyelitis in the spine, pelvis, and femur [5], genitourinary infections [5], lymphadenitis [6], meningitis [8], and skin and soft tissue infections [23] have been reported.…”

“…Acquired resistance to isoniazid is through katG or inhA mutations, to ethambutol through mutations in embB, embR, and other genes in the emb operon, and to rifampicin through mutations in rpoB [26]. Furthermore, the treatment of M. simiae can be challenging since in vitro susceptibility results are not always correlated with in vivo susceptibility [5].…”

“…M. simiae is a slow-growing photochromogenic mycobacterium that was initially considered an environmental pathogen mainly acquired from water [2,4]. This organism can be found in municipal water sources [5], as well as soil, salt, foodstuff, and even air samples [6]. It has been identified in hospital drinking fountains, sinks, and ice machines and can act as a reservoir for nosocomial M. simiae outbreaks [2].…”