The First Case of Concomitant Mycobacterium Genavense Lymphadenitis and EBV-Positive Lymphoproliferative Disorder.

This is the first case of concurrent Mycobacterium genavense lymphadenitis and Epstein-Barr virus (EBV)-positive lymphoproliferative disorder (LPD) in the same lymph node with no immunocompromised history. M. genavense infection is a rare opportunistic infection mainly for human immunodeficiency virus (HIV)-infected patients. Although no immunodeficiency was detected in our patient, our case indicates that the immunodeficiency in the background of EBV latency type III and the immunosuppression by malignant lymphoma itself might induce the M. genavense lymphadenitis. This case highly alerts clinicians to the immunosuppressive state of EBV-positive LPD with latency type III even if any immunodeficient serological factors are not detected.

Mycobacterium conceptionense Bloodstream Infection in a Patient with Advanced Gastric Carcinoma.

A 65-year-old Japanese male farmer with advanced gastric adenocarcinoma and multiple hepatic metastases was admitted to our hospital. Blood culture results were positive on day 5, and Gram-positive rods were detected. According to the results of Ziehl-Neelsen staining and a cultured colony of this bacterium, we suspected a mycobacterial infection. Suspecting a rapidly growing mycobacterium (RGM), we started multidrug therapy with levofloxacin, clarithromycin, and ethambutol, and the patient recovered from the bloodstream infection. Further gene examination (16S rRNA, hsp65, and sodA) revealed an isolate of Mycobacterium conceptionense. M. conceptionense was first identified as an RGM in 2006. Among previous case reports of M. conceptionense infections, bone and soft tissue infections in hosts with a disorder of the normal structure (e.g., surgical sites) were dominant. We report the characteristics of M. conceptionense infection in this first Japanese case report and a review of the literature.

Mycobacterium shigaense Causes Lymph Node and Cutaneous Lesions as Immune Reconstitution Syndrome in an AIDS Patient: The Third Case Report of a Novel Strain Non-tuberculous Mycobacterium.

A 40-year-old man complaining of progressive body weight loss was diagnosed to have acquired immunodeficiency syndrome. Within 2 weeks after the initiation of combination antiretroviral therapy, he developed fever, massive cervical lymphadenopathy and a protruding subcutaneous abscess. A lymph node biopsy and abscess drainage revealed non-caseous granuloma and mycobacterium. The mycobacterium belonged to Runyon II group, but it showed no matches to any previously reported species. According to sequence analyses, the strain was identified as Mycobacterium shigaense. After six months of antimycobacterial treatment, the lesions were all successfully cured. This is the third case report of the novel mycobacterium, M. shigaense, presenting in associatioin with immune reconstitution syndrome.

Disseminated Mycobacterium abscessus Infection Following Septic Arthritis: A Case Report and Review of the Literature.

Mycobacterium abscessus is a rapidly growing mycobacterium found mainly in patients with respiratory or cutaneous infections, but it rarely causes disseminated infections. Little is known about the clinical characteristics, treatment, and prognosis of disseminated M abscessus infection. A 75-year-old Japanese woman who had been treated for 17 years with a corticosteroid for antisynthetase syndrome with antithreonyl-tRNA synthetase antibody developed swelling of her right elbow. X-ray of her right elbow joint showed osteolysis, and magnetic resonance imaging revealed fluid in her right elbow joint. M abscessus grew in joint fluid and blood cultures. She was diagnosed with a disseminated M abscessus infection following septic arthritis. Antimicrobial treatment by clarithromycin, amikacin, and imipenem/cilastatin combined with surgical debridement was administered. Although blood and joint fluid cultures became negative 1 week later, the patient died at 6 weeks from starting antimicrobial treatment. We reviewed 34 cases of disseminated M abscessus infections from the literature. Most of the patients had immunosuppressive backgrounds such as transplantation, use of immunosuppressive agents, hematological malignancy, and end stage renal disease. The duration from onset of symptoms to diagnosis was over 3 months in half of the cases. All fatal cases had positive blood cultures or use of immunosuppressive agents. Clinicians should bear in mind that mycobacterial infections including M abscessus are one of the differential diagnoses in patients with subacute arthritis and soft tissue infections.