Femoropopliteal prosthetic bypass graft infection due to Mycobacterium abscessus localized by FDG-PET/CT scan

Cardiovascular device infections due to rapidly growing Mycobacteria: A review of cases at a tertiary care hospital

Cardiovascular device infection due to rapidly growing mycobacteria (RGM) is rarely encountered in clinical practice. Due to the increasing number of indications and use of cardiovascular devices in an aging population, optimized management of these infections is of great importance. We report seven cases of RGM cardiovascular device infection. Three patients had left-ventricular assist device (LVAD) infections; two patients had cardiovascular implantable device (CIED) infections; and one had an aortic vascular stent infection. Specific cardiac valvular infection was not detected among any of the patients. All patients had a high number of comorbidities which limited some patients from receiving optimal combination antimicrobial therapy. The prognosis of cardiovascular device infections with RGM is guarded with only four patients still alive; however, the treatment approach for each patient varied considerably and often based on concurrent medical conditions, overall adjustments to goals of care, and specific patient preferences. Further analysis of cardiovascular device infections with RGM is warranted to establish a more systematic approach in successful management.

Mycobacterium abscessus bloodstream infection: Unexpected catheter tunnel infection localized by PET/CT

Mycobacterium abscessus is an emerging cause of invasive infection in the immunosuppressed population. We report a case of M. abscessus bloodstream and catheter tunnel infection localized by positron emission tomography/computer tomography (PET/CT) in an allogeneic haematopoietic stem cell transplant recipient. This case highlights the difficulties in treating invasive M. abscessus infection and the potential role of PET/CT in localizing infection and guiding therapy in this population.

Disseminated Mycobacterium abscessus Infection Secondary to an Infected Vascular Stent: Case Report and Review of the Literature

Mycobacterium abscessus is a rapidly growing, multidrug-resistant mycobacteria, commonly associated with pulmonary, skin, and soft tissue infections. We describe a rare case of M abscessus endovascular stent infection; only 3 cases of graft infections have previously been reported.

What, where and why: exploring fluorodeoxyglucose-PET's ability to localise and differentiate infection from cancer

PURPOSE OF REVIEW

To review the utility of FDG-PET imaging in detecting the cause of fever and infection in patients with cancer.

RECENT FINDINGS

FDG-PET has been shown to have high sensitivity and accuracy for causes of neutropenic fever, leading to higher diagnostic certainty in this group. Recent advances in pathogen-specific labelling in PET to identify Aspergillus spp. and Yersinia spp. infections in mice, as well as differentiating between Gram-positive, Gram-negative and mycobacterial infections are promising.

SUMMARY

Patients with cancer are vulnerable to infection and fever, and the causes of these are frequently unclear using conventional diagnostic methods leading to high morbidity and mortality, length of stay and costs of care. FDG-PET/CT, with its unique complementary functional and anatomical information as well as its whole-body imaging capability, has demonstrated use in detecting occult infection in immunocompromised patients, including invasive fungal and occult bacterial infections, as well as defining extent of infection. By demonstrating disease resolution following treatment and allowing earlier cessation of therapy, FDG-PET acts as a key tool for antimicrobial and antifungal stewardship. Limitations include at times poor differentiation between infection, malignancy and sterile inflammation, however, exciting new technologies specific to infectious pathogens may help alleviate that issue. Further prospective randomised research is needed to explore these benefits in a nonbiased fashion.

Mycobacterium abscessus: a rare cause of vascular graft infection

Prosthetic vascular graft infection (PVGI) following vascular reconstructive surgery is an uncommon but serious complication and is associated with high morbidity as well as mortality rate. Staphylococcal species are the most common organisms causing PVGI. Mycobacterium abscessus is a very rare cause of PVGI and poses a significant diagnostic and management dilemma. To the best of our knowledge, we report the third documented case of M. abscessus vascular graft infection that was diagnosed with 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) scan and treated successfully.

What can we learn about valvular heart disease from PET/CT?

Valvular heart disease is a major cause of morbidity and mortality, and with an aging population, its prevalence is increasing. Here, we review the evolving use of positron emission tomography/computed tomography in valvular heart disease, with particular focus on calcific aortic stenosis and infective endocarditis. In principle, the activity of any pathological process can be studied, as long as an appropriate radiotracer can be developed. We will review some of the early data using established tracers in the above and other conditions, providing discussion as to the future research and clinical roles of these techniques. Furthermore, we will discuss the potential impact of novel tracers that are currently under development or testing in preclinical models. It is hoped that such advanced imaging might improve the diagnosis, treatment and outlook for patients with valvular heart disease.

FDG Uptake Pattern on PET/CT Imaging in Non-Infectious Graft of a Patient with Operated Abdominal Aortic Aneurysm

Positron emission tomography using fluorodeoxyglucose is a well known diagnostic tool for routine assessment of the patients with carcinoma. Fluorodeoxyglucose uptake, as a marker of glucose metabolism, is increased in malignant conditions as well as infectious and inflammatory processes. In this case report, findings of postoperative changes in the graft on FDG PET/CT were presented in a patient on follow-up for operated renal cell carcinoma and aortic aneurysm graft surgery. The importance of the FDG uptake pattern has been pointed out for differential diagnosis of infectious and non-infectious conditions.

CONFLICT OF INTEREST

None declared.

[Unilateral purpura of a limb revealing a periprosthetic abscess in an HIV-infected patient]

BACKGROUND

Many diagnoses may be evoked in the presence of purpuric lesions of the lower limbs in HIV-positive patients. We report here on a Staphylococcus aureus abscess around a vascular prosthesis revealed by unilateral purpuric lesions.

PATIENTS AND METHODS

A 43-year-old HIV-positive man was referred to us with febrile purpura of the left lower limb. His past medical history included a crossover iliofemoral arterial bypass. Clinical examination revealed fever and infiltrated purpuric lesions on the left ankle associated with cyanotic left toes. A skin biopsy showed leucocytoclastic vasculitis. A voluminous right iliac abscess was demonstrated by abdominal and pelvic CT scans. S. aureus was isolated from the skin biopsy, two blood cultures and the periprosthetic abscess. The abscess was drained without replacing the prosthesis and antibiotic therapy consisting of oxacillin was given for 6 months, resulting in complete healing.

DISCUSSION

Vascular prosthetic infections are rare events that can occur early or late after surgery. S. aureus is usually the causative infectious agent. Clinical signs are non-specific and include purpuric lesions, which rarely reveal these infections. The organism may generally be isolated from prosthetic materials and blood cultures. CT scan is the recommended test to visualize prosthetic impairment. Treatment comprises prolonged antibiotic therapy adapted in accordance with the bacterial antibiogram, along with surgical debridement and, preferably, prosthetic replacement.

CONCLUSION

This case report describes a unilateral purpura revealing a periprosthetic abscess. Dermatologists must be aware of this sign as a potential indicator of prosthetic infection.

Rare complication after stripping operation: a case report of mycobacterium abscessus infection

Mycobacterium abscessus is an acid-fast nontuberculous mycobacterium that grows rapidly in culture. The organism is found in dust, soil, and water and after trauma, it may infect skin and soft tissue. The organism is rarely found in humans, and infections occurring after cardiovascular surgery are rare clinical events. To our knowledge, only a few cases of hemodialysis arteriovenous graft infection and endocarditis caused by M. abscessus have been described. We reported a first case of patient with M. abscessus graft infection after a stripping operation and skin grafting to a left lower leg ulcer.