Hepatic disseminated mycobacterium infection: a case report and a literature review.

Background: Non-tuberculous mycobacteria (NTM), considered to be less virulent and being pathogenic. People with normal immune function are less likely to be infected. Systemic disseminated infections that spread to the abdominal tissues and organs such as the liver rarely occur with NTM. Case Description: Here, we perform a literature review and report a rare case of disseminated Mycobacterium fortuitum infection with involvement of the liver and hilar lymph node from a 44-year-old immunocompetent woman. The patient experienced prolonged fever and cholecystolithiasis with cholecystitis. Exploratory laparotomy revealed numerous white nodules covering the liver surface and enlarged lymph nodes in the hepatic hilum. Histopathological analysis showed inflammatory granulomas. Auramine O fluorescence staining and acid-fast staining revealed morphological features consistent with NTM. Fluorescence polymerase chain reaction (PCR) melting curve analysis confirmed the presence of Mycobacterium fortuitum. Following diagnosis, the patient was treated with rifampin, isoniazid, pyrazinamide, ethambutol, and clarithromycin. The fever subsided, abdominal pain resolved, and liver function improved, enabling the patient to be discharged. However, 3 months into continued oral administration of these medications, the symptoms recurred. Suspected drug resistance to Mycobacterium fortuitum prompted adjustment of the treatment regimen to alternative antimycobacterial agents. Despite these efforts, due to the unique characteristics of the infection site, repeated sampling for NTM culture and drug susceptibility testing was not feasible, making it impossible to select anti-NTM agents based on susceptibility results. Consequently, the therapeutic response was suboptimal, and the patient ultimately succumbed to multi-organ failure. Conclusions: For patients with multi-organ disseminated infection involving the liver, conventional anti-tuberculosis drugs are less effective, and the infection continues to pose a serious threat that should be considered a high priority. When formulating NTM chemotherapy regimens, combination therapy should be selected based on drug susceptibility testing results, and ongoing monitoring of both drug sensitivity and safety should be ensured throughout the treatment process.