Serious complications of bacteremia caused by Viridans streptococci in neutropenic patients with cancer

We prospectively studied 485 episodes of bacteremia in neutropenic patients with cancer. Viridans streptococci caused a total of 88 episodes (18%). Te n (11%) of these 88 cases were associated with serious complications: acute respiratory distress syndrome (ARDS) plus septic shock (5 cases), ARDS (3) , and septic shock (2). Streptococcus mitis was the species most frequently isolated (7 of 10 episodes). Four viridans streptococci showed a diminishe d susceptibility to penicillin (MICs ranged from 0.25 to 4 mug/mL), and 5 s trains were resistant to ceftazidime (MICs ranged from 2 to >32 mug/mL). Pa tients with viridans streptococcal bacteremia (VSB) who developed serious c omplications were compared with patients with VSB without complications. Se vere oral mucositis (70% vs. 32.5%, respectively; P =.036), high-dose chemo therapy with cyclophosphamide (60% vs. 25%, respectively; P =.043), and all ogeneic bone marrow transplantation (40% vs. 10%, respectively; P =.040) we re the only variables found to be significantly associated with the develop ment of complications. Neither a specific species of viridans streptococci nor resistance to penicillin was associated with the occurrence of complica tions. The mortality rate was higher in case patients than in control patie nts (80% vs. 17.5%, respectively; P<.001). Serious complications associated with VSB occur mainly in patients receiving high-dose chemotherapy with cy clophosphamide before allogeneic bone marrow transplantation who develop se vere oral mucositis; these complications are associated with a high mortali ty rate.