There were no significant associations noted between individual bacteria and the light microscopic appearance of GN, except that 6/7 cases with had crescentic GN, and 3/4 cases of culture-negative endocarditis had crescentic GN. had immune deposits detectable by electron microscopy. Thus, IE-associated GN most commonly presents with AKI and complicates staphylococcal tricuspid valve infection. Contrary to infection-associated glomerulonephritis in general, the most common pattern of glomerular injury in IE-associated glomerulonephritis was necrotizing and crescentic glomerulonephritis. Keywords: crescentic glomerulonephritis, infection-related glomerulonephritis, infective endocarditis, renal biopsy Renal disease due to infective endocarditis (IE) is well established, with the earliest reports of glomerular lesions published over 100 years ago.1, 2, 3 Although initially believed to be primarily embolic,1, 2, 3 it later became clear that over 80% of cases represented focal, segmental, or diffuse proliferative glomerulonephritis (GN) with prominent endocapillary proliferation and occasional infiltrating leukocytes.4, 5, 6 However, the literature describing nephritis associated with IE still relies heavily on autopsy studies conducted in the pre- and early postantibiotic era or small renal biopsy studies from the 1970s. Several reviews have emphasized the evolution occurring in recent Brefeldin A decades in renal complications of infectious diseases in general, with particular emphasis on the change in demographics from younger to older patients, the frequency of comorbidities such as diabetes and HIV, and the change in predominance of infectious agents from primarily streptococcal to a broader array of organisms with predominance of Staphylococci.7, 8, 9, 10 IE occurs in 30 to 60% of patients with bacteremia and carries a mortality rate of 40C50%.11 Over the past decades, IE outcomes have not improved, and infection rates are steadily increasing. 11 Recent case series and reviews of IE have compared findings from current and previous eras, confirmed similar changes in the demographics of the disease, and updated the clinical and pathologic features in both adults and children.5, 12 However, few of these recent reports have focused primarily on IE-related renal lesions, and much of the data currently available still DHCR24 include predominately autopsy-derived information.5, 13 Based on all of the above, we investigated the clinicopathologic characteristics of a large cohort of patients with IE-associated Brefeldin A GN diagnosed by kidney biopsy between 2001 and 2011 in two large nephropathology laboratories. Our data indicate that IE-associated GN in the new era has significantly different clinical and pathologic changes from those described historically. RESULTS Clinical features The clinical characteristics of 49 patients undergoing a renal biopsy with documented IE are detailed in Table 1. Features of note include a male predominance (3.5:1) with a mean age at biopsy of 48 years. Two patients (4%) were children <18 years, and 30% of patients were elderly (60 years of age). Acute renal failure was the most common presenting condition (79%), with hematuria present Brefeldin A in almost all cases (97%), yet typical acute nephritic syndrome in only <10% of cases. Conditions favoring endocarditis were noted in 29 patients including intravenous drug use (29%), prosthetic valves (18%), and prior valvular disease (12%). However, over 50% of patients did not have known prior cardiac disease. Associated comorbid conditions were noted in a minority of patients, the most common being hepatitis C infection (20%) and diabetes mellitus (18%) (Table 1). Table 1 Demographics and clinical characteristics (%/%)38/11 (78/22)?Age (years), mean (range)48 (3C84)???(%)n(%)Hematuria, infection. cMRSA, not further classified as methicillin-sensitive or methicillin-resistant, not further specified, (53%), with methicillin resistance in 56% (Table 2). species were the second most common pathogens found (23%). Less common causes of endocarditis were in four patients, in two, in one, and species in one. Four patients (9%) had culture-negative endocarditis, similar to findings in other series.14, 15 Staphylococcal infection was the most common cause of endocarditis in patients with a history of intravenous drug abuse (77%), with the tricuspid valve or tricuspid and pulmonic valves (in Brefeldin A one patient) affected in 83% and mitral or aortic valves in 17%. There were no.