Mycobacterium abscessus: causing fatal endocarditis after cardiac catheterization

Disseminated Mycobacterium abscessus with endocarditis

We present an uncommon case of endocarditis caused by Mycobacterium abscessus in an immunocompetent patient following a caesarean section. We discuss her turbulent admission course leading to her diagnosis following persistent M. abscessus bacteraemia, medical and surgical management, including a splenectomy and valve resection and repair, and subsequent prolonged course of combination antimicrobials for 24 months post valve surgery. The patient is alive 9 months after completing her treatment and 36 months after her valve surgery. We emphasise the importance of a multidisciplinary team approach in the management of such a complex case.

Mycobacterium abscessus endocarditis post cardiac cathetrisation-a case report and review of 25 cases (2001-2023)

47 year male underwent percutaneous transluminal coronary angioplasty elsewhere, developed fever after two days, and treated empirically in various hospitals for the subsequent two months. Echocardiography showed vegetation in aortic valve and blood cultures were negative. He was then diagnosed as a case of endocarditis due to M. abscessus in our centre by repeated positive blood cultures. After treatment with Imipenem, Amikacin and clarithromycin in the background of pancytopenia, patient was discharged with advice to continue antibiotics and planned for aortic valve replacement. Patient was noncompliant to treatment, readmitted with worsening symptoms, developed multiorgan failure and subsequently died of infection.

Pulmonary valve infective endocarditis caused by Mycobacterium abscessus

Infective endocarditis caused by Mycobacterium abscessus is an uncommon event that, when it does occur, usually requires surgical valve replacement. The pulmonary valve is the least common heart valve involved in infective endocarditis. We present a rare case of isolated pulmonary valve endocarditis with Mycobacterium abscessus in a patient with recurrent sternal infections following repeated coronary artery bypass.

Disseminated Mycobacterium abscessus infection and native valve endocarditis

Mycobacterium abscessus is a rapidly growing mycobacterium. It rarely causes disseminated infection or endocarditis. A 55-year-old male with a history of hepatitis C, liver cirrhosis, intravenous drug use (last use was four years ago), and chronic back pain presented with a three-week history of a right calf nodular lesion. He did not have a fever, chills, rash, dyspnea, or cough. Laboratory data showed mild leukocytosis. Computed tomography of the chest revealed bilateral cavitating nodules. Skin biopsy, sputum, and blood cultures grew Mycobacterium abscessus. Therapy with meropenem, tigecycline, and amikacin was initiated. He was re-admitted with worsening lower back pain. A lumbar magnetic resonance imaging showed destructive changes of L4 and L5 vertebral bodies concerning for osteomyelitis. Blood culture and bone biopsy grew Mycobacterium abscessus again. An echocardiogram was performed due to persistent bacteremia, which revealed large vegetation on the tricuspid valve and small vegetation on the mitral valve. Therapy was changed to eight weeks of amikacin, with cefoxitin and imipenem for twelve months based on drug susceptibility. Treatment of disseminated Mycobacterium abscessus is challenging due to antibiotic resistance. Typically, multidrug therapy is warranted with at least three active drugs. In severe valvular endocarditis, valve replacement may be required.

Haematopoietic stem cell transplant for hyper-IgM syndrome due to CD40 defects: a single-centre experience

Hyper-IgM syndrome due to CD40 deficiency (HIGM3) is a rare disease with only a few reported cases of haematopoietic stem cell transplantation (HSCT). In retrospective study, we reviewed all patients with HIGM3 who underwent HSCT at King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia, between 2008 and 2013. Six patients were identified. Three male and three female patients from three families. The median age of diagnosis was 13 months (range, 1-28 months). All lacked CD40 expression on B cells by flow cytometry. The median time from diagnosis to transplantation was 8.5 months (range, 1-17 months). For all patients, the donors were HLA-identical siblings, with the exception of one patient for whom the donor was a sibling with one antigen mismatch. The conditioning regimen was busulfan and cyclophosphamide in five patients and busulfan, cyclophosphamide and antithymocyte globulin in one patient. For GVHD prophylaxis, cyclosporine and methotrexate was used. All patients engrafted. The survival rate was 100%, with a median follow-up of 54 months (range, 30-116 months). One patient developed acute GVHD. All patients showed complete immune recovery with positive CD40 expression on B cells and discontinued IVIG replacement. Our study shows that HSCT is potentially effective at curing the disease.

Infections caused by Mycobacterium abscessus: epidemiology, diagnostic tools and treatment

INTRODUCTION

Mycobacterium abscessus is an emerging mycobacteria that is responsible for lung diseases and healthcare-associated extrapulmonary infections. Recent findings support its taxonomic status as a single species comprising 3 subspecies designated abscessus, bolletii and massiliense. We performed a review of English-language publications investigating all three of these subspecies. Areas covered: Worldwide, human infections are often attributable to environmental contamination, although the isolation of M. abscessus in this reservoir is very rare. Basic research has demonstrated an association between virulence and cell wall components and cording, and genome analysis has identified gene transfer from other bacteria. The bacteriological diagnosis of M. abscessus is based on innovative tools combining molecular biology and mass spectrometry. Genotypic and phenotypic susceptibility testing are required to predict the success of macrolide (clarithromycin or azithromycin)-based therapeutic regimens. Genotyping methods are helpful to assess relapse and cross-transmission and to search for a common source. Treatment is not standardised, and outcomes are often unsatisfactory. Expert commentary: M. abscessus is still an open field in terms of clinical and bacteriological research. Further knowledge of its ecology and transmission routes, as well as host-pathogen interactions, is required. Because the number of human cases is increasing, it is also necessary to identify more active treatments and perform clinical trials to assess standard effective regimens.