A case report on Mycobacterium houstonense infection after total hip arthroplasty.

BACKGROUND: Mycobacterium houstonense is a category of rapidly growing mycobacteria that is gram-positive, acid-fast, polycrystalline, and non-spore-forming. There have been few reports of human infection caused by Mycobacterium houstonense worldwide. CASE PRESENTATION: We present a case of chronic periprosthetic joint infection caused by Mycobacterium houstonense in an elderly female patient. The patient developed signs of infection after undergoing total hip arthroplasty. Despite receiving antibiotic treatment and revision surgery, the signs of infection recurred repeatedly. Multiple bacterial cultures during the treatment period were negative. Later, we identified the pathogenic bacteria Mycobacterium houstonense through mNGS testing, isolated the bacteria from the ultrasonically centrifuged fluid of the prosthesis and obtained drug sensitivity results. Finally, we performed a revision surgery and treated the patient with moxifloxacin and clindamycin. After treatment, the patient did not show signs of infection recurrence during 24 months of follow-up. CONCLUSION: Through a relevant literature search, we believe that Mycobacterium houstonense may show higher sensitivity to amikacin and quinolone antibiotics. Additionally, clarifying occult infection sources through methods such as gene testing will improve the diagnosis and treatment of periprosthetic joint infection.

Concurrent Mycobacterium genavense infection and intestinal B-cell lymphoma in a pet rabbit (Oryctolaguscuniculus).

A 6-year-old male intact pet rabbit was evaluated for chronic weight loss. A large mass was detected by palpation in the mid-abdomen and ultrasound examination suggested a jejunal location. Explorative laparotomy revealed a nodular mass within the jejunal wall. Histological examination of a biopsy revealed mycobacterial granulomatous enteritis with an atypical lymphoblastic proliferation suggestive of lymphoma. Neoplastic lymphocytes were immunopositive for Pax-5 but negative for CD3, which is diagnostic of a B-cell neoplasm. Numerous acid-fast bacteria were seen within histiocytes and identified by polymerase chain reaction as Mycobacterium genavense, which is a non-tuberculous and opportunistic mycobacterium with zoonotic potential. To the best of our knowledge, this is the first documented case of a concurrent B-cell lymphoma and M. genavense infection in a rabbit. Concomitant mycobacteriosis and lymphoma have been rarely described in animals and the coexistence of neoplasia and mycobacterial infection within the jejunum suggests a potential pathogenetic association. Interestingly, the rabbit owner worked in an anti-tuberculosis clinic, and an anthropic origin of the mycobacterial infection could not be excluded.

Sarcoid-like lesions obfuscating the diagnosis of disseminated Mycobacterium genavense infection in a patient with IL-12Rß1-associated immunodeficiency.

BACKGROUND: Sarcoidosis is a systemic inflammatory disease that is characterized by non-caseating epithelioid-cell granulomas upon histology. However, similar histological findings may also be seen with certain infections. Thus, differentiation from infection is pivotal to ensure appropriate treatment. Here, we present a case of a disseminated infection with Mycobacterium genavense owing to an interleukin 12 receptor subunit beta 1 (IL-12Rß1) associated immunodeficiency in a previously healthy female who was initially misdiagnosed with sarcoidosis. M. genavense is a nontuberculous mycobacterium which can cause lymphadenopathy, gastrointestinal and bone marrow infiltration in immunocompromised patients. With this case report we aim to highlight that an infection with M. genavense on the ground of a genetic defect of mycobacterial immune control may represent a rare differential diagnosis of sarcoidosis. CASE PRESENTATION: A 31-year-old female was referred to our hospital with progressive lymphadenopathy, hepatosplenomegaly, pancytopenia and systemic inflammation. She had previously been evaluated for generalized lymphadenopathy in another hospital. At that time, lymph node biopsies had revealed sarcoid-like lesions and a systemic corticosteroid treatment was initiated based on a putative diagnosis of sarcoidosis. When her condition worsened, she was transferred to our university clinic, where the diagnosis of disseminated M. genavense infection owing to an inborn interferonopathy was made. Her family history revealed that her brother had also suffered from IL-12Rß1 deficiency and had died from a systemic infection with M. genavense at the age of 21. The patient received antimycobacterial treatment combined with subcutaneous type I interferon, which eventually led to a gradual improvement over the next months. CONCLUSIONS: Differentiating between sarcoidosis and sarcoid-like lesions secondary to infections may be challenging, especially when pathogens are difficult to detect or not expected in an apparently immunocompetent patient. Patients with IL-12Rß1-associated immunodeficiency may be asymptomatic until adulthood, and disseminated M. genavense infection on the grounds of an IL-12Rß1-associated immunodeficiency may represent a rare differential diagnosis of sarcoidosis.

Case report: Mycobacterium neoaurum infection during ICI therapy in a hepatocellular carcinoma patient with psoriasis.

We report here a patient with advanced hepatocellular carcinoma (HCC) and psoriasis treated with immune checkpoint inhibitor (ICI) therapy who experienced tumor partial response and psoriatic exacerbation. Meanwhile, the patient contracted mycobacterium neoaurum during the treatment period, while it was an opportunistic infection and mainly happened in immunosuppressed patients. We discussed the possibility that this infection was an ICI-associated infection independent of immunosuppression due to dysregulated immunity, which was the result of the effects of immunotherapy and autoimmune disease (AID), and the characteristics and treatment of M. neoaurum, which was rarely reported in China. This case highlights the fact that some infections can be precipitated by ICIs in the absence of immunosuppressive treatment, especially the patients with AID.

Sclerosing mesenteritis due to Mycobacterium genavense infection: A case report.

RATIONALE: Since its first identification in the early 1990s, Mycobacterium genavense has been considered and opportunistic pathogen. It mainly causes gastrointestinal symptoms, but also disseminated infections in severely immunosuppressed patients. Sclerosing mesenteritis is a long-term complication with high morbidity and mortality. As it is a rare condition, there are no specific guidelines for its management. We report a challenging case of persistent M. genavense infection, and propose surgery as an alternative treatment strategy. PATIENT CONCERNS: A 38-year-old Caucasian man presented to the emergency room with fever, abdominal pain, and night sweats for 3 months. HIV screening revealed a previously unknown HIV-1 infection, with a CD4 cell count of 216 cell/µL and viral load of 361.000 copies/mL at diagnosis. A body CT-scan showed mild splenomegaly as well as mesenteric and retroperitoneal enlarged lymph nodes. Fine needle aspiration revealed the presence of acid-fast bacilli, but mycobacterial cultures were negative. In the second sample, 16S RNA sequencing yielded a diagnosis of M. genavense infection. Despite 2 years of corticosteroids and antimycobacterial treatment excluding rifampicin due to a severe cutaneous reaction, there was no clinical improvement and an increase in the mesenteric lymph node size was observed, with a sclerosing transformation of the mesentery. A surgical approach was proposed to release small bowel loops and to remove fibrin. A second surgery was required due to an acute peritonitis ought to yeyunal segmental isquemia and perforation. Finally, the patient evolved favorably, and antimycobacterial drugs were suspended without relapse. LESSONS: Despite a prolonged multidrug strategy, some patients develop persistent M. genavense infection. Once sclerosing mesenteritis is established, clinicians have few treatment options. Surgery should be considered in patients with sclerosing mesenteritis or bowel obstruction. The combination of medical and surgical treatment could be a potential cure for these patients.

Extrapulmonary tuberculosis and COVID-19 infection coexisting in concurrent necrotising fasciitis with deep space infection of neck: an unusual presentation.

Ludwig's angina is a rapidly spreading, potentially fatal infection of deep fascial spaces of the neck leading to airway oedema and death. This, in recent times when associated with COVID-19 infection, possess treatment challenges making the patient susceptible to opportunistic infections with reduced healing potential. Owing to the multifactorial aetiology in our case and addressing them at the earliest, it is important to achieve favourable outcomes. The space infection that seeded with untreated trivial dental caries progressed to necrotising fasciitis of neck with mycobacterial growth on cartridge-based nucleic acid amplification test for tuberculosis testing. The presence of Mycobacterium organisms should be speculated in patients with pulmonary signs of tuberculosis (TB) because a suppurative TB lymphadenitis of neck could also have the same presentation. The decisive moment in successful outcome was identification of mycobacteria in COVID-19 infected patient, thereby allowing to initiate the antitubercular therapy along with surgical debridement. Thus, medical management of patient with cohabiting infections is difficult task and needs appropriate addressal.

The Contribution of Human Herpes Viruses to γδ T Cell Mobilisation in Co-Infections.

γδ T cells are activated in viral, bacterial and parasitic infections. Among viruses that promote γδ T cell mobilisation in humans, herpes viruses (HHVs) occupy a particular place since they infect the majority of the human population and persist indefinitely in the organism in a latent state. Thus, other infections should, in most instances, be considered co-infections, and the reactivation of HHV is a serious confounding factor in attributing γδ T cell alterations to a particular pathogen in human diseases. We review here the literature data on γδ T cell mobilisation in HHV infections and co-infections, and discuss the possible contribution of HHVs to γδ alterations observed in various infectious settings. As multiple infections seemingly mobilise overlapping γδ subsets, we also address the concept of possible cross-protection.

Pulmonary mycobacterial infection is associated with increased mortality in patients with acute respiratory distress syndrome.

ABSTRACT: Although pulmonary mycobacterial infection is associated with acute respiratory distress syndrome (ARDS) in critically ill patients, its clinical implication on patients with ARDS has not been clearly elucidated. The aim of study was to investigate the clinical significance of pulmonary mycobacterial infection in patients with ARDS.Between January 2014 and April 2019, medical records of 229 patients with ARDS who met the Berlin criteria and received invasive mechanical ventilation in medical intensive care unit were reviewed. Clinical characteristics and the rate of mortality between patients with and without pulmonary mycobacterial infection were compared. Factors associated with a 28-day mortality were analyzed statistically.Twenty two (9.6%) patients were infected with pulmonary mycobacteria (18 with tuberculosis and 4 with non-tuberculous mycobacteria). There were no differences in baseline characteristics, the severity of illness scores. Other than a higher rate of renal replacement therapy required in those without pulmonary mycobacterial infection, the use of adjunctive therapy did not differ between the groups. The 28- day mortality rate was significantly higher in patients with pulmonary mycobacterial infection (81.8% vs 58%, P = .019). Pulmonary mycobacterial infection was significantly associated with 28-day mortality (hazard ratio 1.852, 95% confidence interval 1.108-3.095, P = .019).Pulmonary mycobacterial infection was associated with increased 28-day mortality in patients with ARDS.

Aortic aneurysm and aortic graft infection related to Mycobacterium bovis after intravesical Bacille Calmette-Guérin therapy-a case series.

BACKGROUND: So called "mycotic" aortic aneurysms account for only 0.7 to 1.3% of all aortic aneurysms and are commonly caused by Staphylococcus aureus and Salmonella species. Bacillus Calmette-Guérin (BCG), a live attenuated strain of Mycobacterium bovis, is part of the therapy of non-muscle-invasive bladder cancer (NMIBC). CASE PRESENTATION: We report a case series of three patients with a mycobacterial graft infection related to BCG after surgical treatment of a presumed mycotic aortic aneurysm as an extremely rare complication after NMIBC treatment. All three patients developed aortic aneurysm after BCG instillation and subsequent mycobacterial graft infection. CONCLUSION: Diagnosis requires a high degree of suspicion because of its nonspecific symptoms and imaging. The pathogen is not detected by standard microbiological testing. Treatment includes triple antimycobacterial therapy and radical surgical interventions. Graft preservation may be considered if no anastomosis is involved.

Mycobacterium chimaera After Aortic Valve Replacement Causing Aortic Rupture and Prosthetic Valve Endocarditis.

A 20-year-old man with severe aortic insufficiency received a mechanical aortic valve replacement. Afterward he subsequently presented with an aortic root dissection, pseudoaneurysm, and prosthetic valve endocarditis requiring surgical reinterventions twice with a positive Mycobacterium chimaera tissue culture despite prolonged antimycobacterial therapy. This is the first reported clinical case of M chimaera in Western Canada and the first with M chimaera-associated aortic dissection and pseudoaneurysm.

Granulomatous interstitial nephritis in the setting of disseminated Mycobacterium simiae: a rare presentation of immune reconstitution inflammatory syndrome.

Disseminated Mycobacterium simiae is a rare opportunistic infection reported most commonly in advanced human immunodeficiency virus (HIV) infection. Treatment can be further complicated by the occurrence of severe immune reconstitution inflammatory syndrome (IRIS). We present the first case of disseminated multi-drug-resistant M. simiae in the setting of advanced HIV, complicated by IRIS in the form of granulomatous interstitial nephritis causing acute renal failure. This case highlights the importance of recognizing rare complications of IRIS, as delays in therapy can be life threatening.

Long-term ulcerations caused by Mycobacterium lepromatosis.

Patients with leprosy rarely present ulcerated lesions that can appear during reactional states like Lucio's phenomenon (LP), as in our case. LP is a rare complication of multibacillary leprosy due to massive bacilli invasion of endothelial cells causing a thrombotic syndrome. The initial macular lesion is purpuric followed by multiple infiltrated papules and nodules, some of them ulcerated, associated to loss of sensation on lower limbs. The importance of recognizing ulcers as a specific cutaneous manifestation of leprosy allows early diagnosis and treatment, and therefore avoiding the development of disabilities and persistence of illness. Infection by Mycobacterium lepromatosis is associated with LP and it should be especially sought in patients from endemic areas.

Non-tuberculosis Mycobacterium Tenosynovitis with Rice Bodies in a Patient with Systemic Lupus Erythematosus.

Infectious disease with various presentations in systemic lupus erythematosus often resembles lupus flare. A 37-year-old woman presented with a swollen left index finger that had not resolved, despite 7 years of immunosuppressive treatment. MRI showed rice-body formation in the flexor tendon sheath and tenosynovectomy demonstrated chronic synovitis with epithelioid granuloma. A mycobacterial culture confirmed invasive mycobacterial tenosynovitis due to Mycobacterium chelonae. The patient was treated with moxifloxacin and clarithromycin and completely recovered.

Analysis of the causes of cervical lymphadenopathy using fine-needle aspiration cytology combining cell block in Chinese patients with and without HIV infection.

BACKGROUND: Cervical lymphadenopathy refers to a frequently observed clinical presentation in numerous pathological conditions. A wide spectrum of diseases can cause cervical lymphadenopathy, irrespective of the fact that the patients are infected with HIV or not. The present study focuses on validating whether the causes of cervical lymphadenopathy differ significantly in HIV and non-HIV patients by using fine-needle aspiration cytology (FNAC) combining cell block. METHODS: A total of 589 patients with cervical lymphadenopathy were recruited in the FNA clinic. The samples were obtained by an auto-vacuumed syringe that benefited the sampling more materials. The cytological smears were prepared by Hematoxylin and Eosin (HE), Periodic Acid Schiff (PAS), Gomori's methenamine silver (GMS) and acid-fast staining. Cell blocks were made if required, and immunohistochemistry stain was performed on the cell block section. RESULTS: The study found 453 (76.9%) patients with HIV and 136 (23.1%) patients without HIV infection. The average age of HIV-infected patients was 34.8 ± 10.2 years, which was significantly lower than that of non-HIV-infected patients (42.9 ± 18.1 years) (p < 0.01). Of all patients infected with HIV, 390 (86.1%) were males. This proportion was significantly higher than that of non-HIV-infected patients [65/136 (47.8%)] (p < 0.01). The major causes of cervical lymphadenopathy in HIV positive patients were mycobacterial infection (38.4%), reactive hyperplasia (28.9%), non-specific inflammation (19.9%), and malignant lesions (4.2%). In contrast, the most common causes in HIV negative patients were reactive hyperplasia (37.5%), malignancy (20.6%), non-specific inflammation (19.1%) and mycobacterial infection (12.5%). Opportunistic infections such as non-tuberculous mycobacteria (4.2%), cryptococcosis (1.5%), Talaromyces marneffei (1.5%) and other fungi (0.4%) were found only in HIV-infected individuals. Non-Hodgkin's lymphoma (2.4%) was the most common malignant lesion in patients with HIV infection, followed by Kaposi's sarcoma (0.9%) and metastatic squamous cell carcinomas (0.7%). However, the most common malignancy in non-HIV-infected patients was metastatic carcinomas (14%) including small cell carcinomas, adenocarcinomas, squamous cell carcinomas and hepatocellular carcinoma, which were noticeably greater than the HIV patients (p < 0.01). CONCLUSIONS: There were significantly different causes of cervical lymphadenopathy in HIV infected and non-HIV infected patients. FNAC was a useful diagnostic method for differential diagnosis of cervical lymphadenopathy.