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Abstract: FR-PO718

Lactobacillus Endocarditis-Associated Crescentic Glomerulonephritis

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: From Inflammation to Fibrosis


  • El Mouhayyar, Christopher, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Al Jurdi, Ayman, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Seethapathy, Harish Shanthanu, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Nissaisorakarn, Pitchaphon, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Jeyabalan, Anushya, Massachusetts General Hospital, Boston, Massachusetts, United States

Infection-related glomerulonephritis (IRGN) encompasses a wide range of clinical and pathologic manifestations. Up to 50% of patients can develop persistent kidney impairment and 1/3 can progress to kidney failure. (Medjeral-Thomas et al. Clin J Am Soc Nephrol. 2014.) Staphylococcus and Streptococcus are the most common pathogens isolated however IRGN in the setting of lactobacillus is considered rare.

Case Description

A 79-year-old male with history significant for heart failure with preserved ejection fraction, bioprosthetic AVR, and chronic kidney disease (CKD) IIIb thought to be secondary to uncontrolled hypertension and recurrent AKI presented with dyspnea on exertion. Physical exam revealed signs of volume overload and a new systolic murmur. Echocardiogram showed vegetation consistent with bioprosthetic valve endocarditis. Blood cultures grew Lactobacillus species and upon reviewing his medication list probiotics was noted. His course was complicated by acute on chronic kidney injury requiring dialysis. Workup included a 24-hour urine collection showing 2.4g of protein and 1.3g of albumin, normal serum free light chain ratio, normal serum protein electrophoresis, and normal C3 and C4 levels. Kidney biopsy performed revealed necrotizing and crescentic glomerulonephritis with immunofluorescence positive for IgG, IgM and C3; consistent with IRGN. Patient was started on ampicillin and a steroid course was proposed. However, the patient and his family declined given risk of exacerbation of infection and decision was made to pursue conservative management with antibiotics and dialysis which the patient is still on.


The pathogenesis of IRGN involves glomerular immune complex deposition along with classical complement pathway activation. This is frequently associated with a reduction in serum C3 and normal C4 levels, but as illustrated in our case C3 levels can be normal. The mainstay of treatment is withdrawal of enticing agent (probiotics), treatment of the underlying infection and supportive care. The utilization of systemic steroids in these patients is highly controversial given no evidence of efficacy in IRGN patients at low risk for progression (Arivazhagan et al. Kidney Int Reports. 2022). They can be considered in specific cases, such as patients with diffuse crescentic and rapidly progressive GN.