A case of severe Mycobacterium thermoresistibile pneumonia

Mycobacterium thermoresistibile is a thermotolerant nontuberculous mycobacterium which can rarely result in human infection. Although immunosuppression has been identified as a risk factor for infection, it is possible that mycobacterial laboratories may have previously under-recognized M. thermoresistibile as standard mycobacterial incubation temperatures are suboptimal for culture of this organism. Here, we present a case of severe M. thermoresistibile pneumonia associated with achalasia requiring life support in the intensive care unit. We speculated that the interplay between specific host and environmental risk factors contributed to acquisition of infection. Infection with this fastidious organism required prolonged treatment with multiple antimicrobials and adjunctive therapeutic drug monitoring which led to clinical cure despite residual lung injury. We also reviewed literature documenting cases of human infection with M. thermoresistibile. The diagnosis of M. thermoresistibile requires a high degree of clinical suspicion considering its association with immunosuppressive conditions, postulated environmental inoculation and eponymous culture growth characteristics.