We report a linezolid-resistant Enterococcus faecalis infection in a cord blood stem cell transplant recipient previously treated with linezolid for bloodstream infections by vancomycin-resistant enterococci. Sequencing showed a G2576U mutation in the 23S rRNA gene. Because of the important niche of linezolid in cancer treatment, linezolid-resistant E. faecalis is noteworthy.
CASE REPORTA 37-year-old woman underwent allogeneic cord blood stem cell transplantation as therapy for acute myeloid leukemia in second remission at Roswell Park Cancer Institute (Buffalo, N.Y.). The pretransplant course was complicated by invasive pulmonary filamentous fungal infection morphologically consistent with an Aspergillus species. The patient had a complete response to voriconazole. The posttransplant course was complicated by prolonged neutropenia and acute graft-versus-host disease (GVHD) involving skin and bowel, necessitating a prolonged course of high-dose corticosteroid therapy. Multiple courses of antibiotics were administered for persistent neutropenic fever and polymicrobial bacteremia with Klebsiella pneumoniae and a viridans group streptococcus. Six weeks after transplant, vancomycin-resistant Enterococcus gallinarum bacteremia developed and was treated initially with quinupristindalfopristin and then with linezolid due to hepatic toxicity associated with quinupristin-dalfopristin. Three months after transplant, the patient developed sternal chest pain and a computed tomography scan showed a lytic lesion in the sternum. A culture of a needle aspirate grew vancomycin-resistant Enterococcus faecium. The patient was treated with a 7-week course of linezolid for sternal osteomyelitis. A transthoracic echocardiogram did not show evidence of vegetations; a transesophageal echocardiogram was not performed because of mucositis associated with persistent neutropenia.Two weeks after linezolid therapy was stopped, bilateral pulmonary infiltrates developed, and the patient required mechanical ventilation. Bronchoalveolar lavage fluid grew linezolid-resistant Enterococcus faecalis and cytomegalovirus. Treatment with foscarnet and intravenous immunoglobulin was initiated for presumed cytomegalovirus pneumonitis. The E. faecalis isolate was considered to be a respiratory colonizer unrelated to the respiratory failure.Further complications developed, including pancolitis associated with GVHD, colonic pseudo-obstruction, progressive liver failure (probably related to GVHD and medication-related toxicity), azotemia, and Candida glabrata cholecystitis requiring percutaneous drainage. In the setting of refractory multiorgan disease, aggressive therapy was withdrawn and the patient died.