Membranoproliferative glomerulonephritis complicating Propionibacterium acnes infection

Background Propionibacterium acnes (P. acnes) is a common microbe of the skin and mucosal surfaces rarely considered a true pathogen. However, it has been reported to cause serious infections. Subsequent ongoing low-grade antigenaemia may, in turn, lead to an immune-mediated glomerulonephritis with various renal histologies including that of membranoproliferative glomerulonephritis (MPGN).MethodsHere, we describe two cases of P. acnes infection-induced MPGN and their treatment.ResultsBoth patients were successfully treated by the eradication of the infection. One patient also received immunosuppressive medication prior to the correct diagnosis.ConclusionsA vigorous exclusion of infection is warranted in MPGN type I or immune-complex-mediated MPGN and may sometimes yield a diagnosis of secondary MPGN.