Successful treatment of Staphylococcus aureus bacterial endocarditis in a renal transplant recipient

Endocarditis in kidney transplant recipients: a systematic review

Infective Endocarditis (IE) carries significant mortality. Bacteremia, which is a predisposing factor for IE, occurs more frequently in immunocompromised individuals. Interestingly, IE in kidney transplant recipients has not been adequately described. The aim of this study was to systematically review all published cases of IE in kidney transplant recipients and describe their epidemiology, microbiology, clinical characteristics, treatment and outcomes. A systematic review of PubMed (through 13^th December 2019) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE in kidney transplant recipients was performed. A total of 60 studies, containing data of 117 patients, were included in the analysis. The most common causative pathogens were gram-positive microorganisms in 57.4%, gram-negative microorganisms in 14.8%, fungi in 20%, while in 18.9% of cases, IE was culture-negative. Aortic valve was the most commonly infected valve followed by mitral, tricuspid and the pulmonary valve. Diagnosis was set with a transthoracic ultrasound in half the cases, followed by transesophageal ultrasound and autopsy. Fever was present in most cases, while embolic phenomena were noted in two out of five cases. Aminoglycosides, cephalosporins and aminopenicillins were the most commonly used antimicrobials, and surgical management was performed in one out of three cases. Clinical cure was noted in 60.9%, while overall mortality was 45.3%. To conclude, this systematic review thoroughly describes IE in kidney transplant recipients and provides information on epidemiology, clinical presentation, treatment and outcomes. Moreover, it identifies the emerging role of Enterococci, gram-negatives and fungi in IE in this population.

Influence of bacterial superantigen TSST-1 against the anti-proliferative efficacy of immunosuppressive drugs and interleukin 2 production in peripheral blood mononuclear cells of hemodialysis patients and healthy subjects

We investigated the influence of bacterial superantigen on the efficacies of immunosuppressive drugs on the blastogenesis of peripheral-blood mononuclear cells of 27 hemodialysis patients awaiting renal transplantation. The IC(50) values for prednisolone, methylprednisolone, cyclosporine, and tacrolimus evaluated in the superantigen-stimulated cells were significantly higher than those evaluated in concanavalin A-stimulated cells (p = 0.0002-0.018). Interleukin-2 amounts produced from superantigen-stimulated cells were significantly larger than those from concanavalin A-stimulated cells (p = 0.0363). These results suggest that superantigen attenuates the suppressive efficacies of glucocorticoids and calcineurin inhibitors by stimulating lymphocytes of hemodialysis patients awaiting transplantation to overproduce interleukin-2.

Severe endocarditis in transplant recipients--an epidemiologic study

Infective endocarditis (IE) is reported with an incidence of 6/100,000 inhabitants in the general population. Even though immunosuppression predisposes to systemic infection, reports regarding IE after solid organ transplantation (SOT) are sparse. From 1989 to 2004, 2556 patients underwent SOT at the University Hospital Innsbruck. During this period, 27 transplant recipients were diagnosed IE. Nine patients (33.3%) were diagnosed at autopsy, eight patients (29.6%) were cured by antibiotic treatment and 10 patients (37.1%) underwent surgery. Overall mortality was 44.4% (12 patients). Staphylococcus was the predominant microorganism in 16 cases (59.3%), fungal infection was present in four patients (14.8%). Incidence of IE was 1% (95% CI: 0.67-1.49), indicating a 171-fold risk compared with the overall population. IE after SOT constitutes a significant problem and is associated with an excessive high mortality. Alertness to this condition is indicated, as we might diagnose more cases of IE in the future.