Linezolid-induced interstitial nephritis in a kidney-transplant patient

Linezolid is a recent oral antibiotic used in drug-resistant Gram-positive cocci infections. Herein, we report on the first case of linezolid-related acute renal failure in a kidney-transplant patient. A 60-year-old male having autosomic polycystic kidney disease with liver involvement, on cyclosporin A, mycophenolate mofetil and very low dose prednisolone, presented with an Enterococcus faecium abscess of a huge liver cyst, which was treated by percutaneous drainage and linezolid therapy. Eight days after starting linezolid, he presented with acute renal failure, i.e. serum creatinine increased from 136- 221 micromol/l, associated with mild hypereosinophilia, anemia and thrombocytopenia. There was no skin rash, arthralgia, eosinophiluria or proteinuria. The transplant kidney biopsy, performed 15 days after the beginning of linezolid therapy, showed interstitial nephritis and focal tubular atrophy. After linezolid withdrawal and increasing prednisolone daily dose to 20 mg/d, within a few days, serum creatinine had decreased; after 2 and 4 weeks post linezolid withdrawal, his serum creatinine was 166 and 159 micromol/l, respectively. Because of the potential side effects of linezolid, i.e. myelosuppression and possibly nephrotoxicity, we recommend close monitoring of these parameters when linezolid therapy is attempted in kidney transplant patients.