The prevalence of non-tuberculous mycobacteria (NTM) infections has been on the rise in recent years, especially among the elderly population and other immunocompromised groups. Risk factors for NTM infections include advanced age, preexisting pulmonary diseases, and low body mass index. This study presents a case of NTM pulmonary disease attributed to Mycobacterium intracellulare, which was rapidly identified using metagenomic next-generation sequencing (mNGS). An 82-year-old male presented with persistent fever, cough, and shortness of breath. Initial assessments revealed an elevated white blood cell count and high-sensitivity C-reactive protein, with chest CT showing newly formed nodular shadows and cavity formation. Sputum tests confirmed NTM infection through positive acid-fast staining and mNGS, which rapidly identified M. intracellulare within 48 hours. Subsequent sputum samples confirmed the diagnosis using traditional methods. The patient had a complex medical history, including pulmonary tuberculosis, chronic pancreatitis, chronic hepatitis B, diabetes, and malnutrition. The patient was treated with a combination of cefotaxime, moxifloxacin, clarithromycin, and acetylcysteine, in addition to receiving nutritional support. After the treatment, there was an improvement in symptoms, normalization of body temperature, and a decrease in cough and sputum production. This case highlights the significance of mNGS in promptly diagnosing and treating NTM pulmonary disease, especially in elderly patients with various underlying health conditions. The collaborative effort among different medical specialties enabled more thorough patient care, ultimately leading to better outcomes. Incorporating cutting-edge diagnostic techniques such as mNGS alongside a holistic treatment approach is crucial for the successful management of NTM infections in at-risk populations.

All members of the genus Mycobacterium are collectively labeled as \"non-tuberculous mycobacterium\" (NTM), with the exception of the Mycobacterium tuberculosis complex and M. leprae. Recently, the incidence of NTM infection and number of cases have been increasing, but their identification remains difficult in some countries. Usually, NTM infections and diseases are associated with primary immunodeficiency diseases (PIDs), and their prognoses can be improved with a timely diagnosis and appropriate treatment. Here, we report a case of a 3-year-old boy with disseminated NTM disease (Mycobacterium intracellulare) and interferon-γ receptor 1 (IFNGR1) deficiency. He presented with skin and soft-tissue disease, disseminated osteomyelitis, and pulmonary disease. Initially, we suspected an infection due to the Bacillus Calmette-Guérin vaccine but later suspected Langerhans cell histiocytosis. Following oral treatment of azithromycin, rifampicin, and ethambutol, his condition improved progressively according to clinical and imaging manifestations. This case highlights the importance of early identification of the pathogen in a timely prescription of specific treatments in PIDs patients. We also discuss our experience of treatment of M. intracellulare disease in patients with IFNGR1 deficiency.

UNASSIGNED: Nontuberculous mycobacterial (NTM) infections of the musculoskeletal system are uncommon. Such infections are typically acquired by direct inoculation after penetrating trauma, surgical procedures, or needle injections. There are no reported cases of NTM infection after arthrocentesis for idiopathic hemarthrosis of the knee. Here we report a case of NTM infection in the knee that developed after arthrocentesis for idiopathic hemarthrosis of the knee.
UNASSIGNED: The patient was an 85-year-old woman who experienced swelling of the left knee. An arthrocentesis was carried out, and hemarthrosis was found. The patient was referred to our hospital for repeated recurrence of hematoma of the knee. Significant swelling was observed in the suprapatellar sac. Magnetic resonance imaging examination revealed a mass at the suprapatellar sac. Laboratory data showed elevation of inflammatory markers. Debridement was performed under arthroscopy and samples were collected for culture. Although routine microbiological cultures were negative, the patient continued to experience knee swelling and laboratory data showed high C-reactive protein levels. Therefore, open debridement was carried out. At 4 weeks after the first surgical treatment, intraoperative cultures yielded Mycobacterium intracellulare. At this point, we diagnosed septic arthritis of the knee due to NTM infection. The patient showed an excellent prognosis with three-drug medical treatment for 1 year.
UNASSIGNED: Clinically, diagnosis of septic arthritis due to NTM infection is not easy. Because selection of examination depends on clinical suspicion, NTM infections should be considered for patients with elevation of inflammatory markers after episodes of surgical procedures, and/or needle injections.

Mycobacterium avium intracellulare (MAI) is an opportunistic infection that typically manifests itself as pulmonary infection. In immunocompromised patients, however, MAI can uncommonly cause disseminated disease and diffuse gastrointestinal involvement. Small bowel obstruction with concurrent MAI infection is rarely documented in literature. Here, a 60-year-old female with a past medical history significant for a gastrointestinal stromal tumor, two small bowel obstructions, and a bowel perforation repair presented to the emergency department with sharp abdominal pain due to a small bowel obstruction. Cultures obtained from the laparoscopic release of small bowel obstruction confirmed the presence of MAI. An antibiotic course of ethambutol, azithromycin, and rifampin was initiated and continued upon transfer to a long-term acute care facility. We describe this case to highlight the possibility of MAI infection in patients with postoperative abdominal pain resulting from small bowel obstruction, review the underlying pathophysiology, and discuss its epidemiology.

Recurrence of oestrogen receptor (ER)-positive breast cancer rarely occurs postoperatively after a long period. Breast cancer cells survive and settle in distant organs in a dormant state, a phenomenon known as \"tumour dormancy.\" Here, we present a 66-year-old woman with recurrence of ER-positive breast cancer in the left lung 23 years after surgery accompanied with non-tuberculous mycobacterium infection (NTM). At the age of 43 years, the patient underwent a right mastectomy and adjuvant hormonotherapy to completely cure breast cancer. Twenty-three years after the operation, when the patient was 66 years old, computed tomography presented nodular shadows in the lower lobes bilaterally with bronchiectasis and ill-defined satellite tree-in-bud nodules. Mycobacterium intracellulare was detected in cultured bronchoalveolar lavage fluid obtained from the left lower lobe by bronchoscopy. Rifampicin, ethambutol, and clarithromycin were started, which resulted in shrinkage of the nodule in the right lower lobe and satellite nodules; however, the nodule in the left lower lobe increased in size gradually. Wedge resection of the left lower lobe containing the nodule by video-assisted thoracoscopic surgery was performed, which demonstrated that the nodule was adenocarcinoma in intraoperative pathological diagnosis; therefore, a left lower lobectomy and mediastinal lymph node dissection were performed. The tumour was revealed to be consistent with recurrence of previous breast cancer according to its morphology and immunohistochemical staining. Furthermore, caseous epithelioid cell granulomas existed in the periphery of the tumour. It is reported that inflammatory cytokines induce reawakening of dormant oestrogen-dependent breast cancer and, in our case, NTM infection might have stimulated the dormant tumour cells in the lower lobe.

Axillary lymphadenitis caused by non-tuberculous mycobacteria is rare and has been reported in immunocompromised hosts. Herein, we report the case of a 67-year-old man without immunodeficiency who developed right axillary lymphadenitis caused by Mycobacterium intracellulare and showed a small nodular shadow in the left pulmonary apex. Biopsy of the right axillary lymph node revealed several epithelioid granulomas, and the culture of the lymph node aspirate yielded Mycobacterium intracellulare. The lymph node lesion and left lung apex shadow resolved spontaneously after careful outpatient monitoring. This case suggests that axillary lymphadenitis could be caused by Mycobacterium intracellulare in an immunocompetent patient.

Mycobacterium haemophilum is a slow-growing, non-tuberculous mycobacteria that causes cutaneous infection. We describe a case of cutaneous infection in a 68-year-old Japanese man with polymyositis. This was caused by M. haemophilum harboring one base insertion in gene sequence. At first, the causal microorganism was misidentified as M. intracellulare by COBAS® TaqMan® MAI test. However, poor growth on Ogawa media and growth enhancement on 7H11C agar around a hemin-containing disk prompted us to reinvestigate the causal microorganisms, which were revealed to be M. haemophilum. Amplified polymerase chain reaction products were sequenced, and the 16S rRNA gene, rpoB, hsp65 and internal transcribed spacer region sequences showed a 100%, 100%, 99.66% and 99.7% match, respectively, with the corresponding regions of M. haemophilum, but it harbored a novel gene sequence in hsp65. The sequences determined by gene analysis of the M. haemophilum strain were deposited into the International Nucleotide Sequence Database. Although numerous cases of M. haemophilum infection have been reported in other countries, only six cases have been reported in Japan to date. It could be possible that this novel mutation lead to misdiagnosis. As M. haemophilum prefers a lower growth temperature (30-32°C) and it requires iron in the culture medium, M. haemophilum could be misidentified or overlooked. Accordingly, a M. haemophilum infection should be considered in cases of cutaneous infection of the body sites, of which surface temperature is low.

There are few reported cases of post-operative spondylitis caused by Mycobacterium intracellulare. A 75-year-old female presented to our hospital with low back pain and paraparesis after a fall. The radiologic examination revealed compression fractures of L1, L3 and L4 and an epidural hematoma compressing the spinal cord. The dark-red epidural hematoma was urgently evacuated. Four weeks post-operatively, neurologic deficits recurred with fever. On magnetic resonance image, an epidural abscess and osteomyelitis were detected in the previous operative site. Five weeks post-operatively, revision was performed with multiple biopsies. The specimen were positive for acid-fast bacilli and traditional anti-tuberculous medications were started. Because the Polymerase Chain Reaction for non-tuberculous mycobacterium (NTM) was positive, the anti-tuberculous medications were changed to anti-NTM drugs. However, the neurologic deficits did not improve and persistent elevation of erythrocyte sedimentation rate and C-reactive protein were noted. Eight weeks after the revision, Mycobacterium intracellulare was detected in the specimen cultures. Despite supportive care with medication, the patient died due to multiple organ failure.