Review of streptococcal bloodstream infections at a comprehensive cancer care center, 2000–2011

Abstract

To determine the comparative rates, clinical characteristics, and outcomes of invasive infections due to specific streptococcal types in patients with cancer. Review of electronic medical records of patients with non-viridans group streptococcal bloodstream infection (BSI) at the MD Anderson Cancer Center from 2000 to 2011. 550 streptococcal BSI were identified. The largest number of cases were caused by Streptococcus pneumoniae (251), group B Streptococcus (147), and gamma-hemolytic streptococci (55). Risk factors for developing a severe streptococcal infection included older age, being neutropenic at onset of BSI, and having a respiratory source of infection. Between 2000-2001 and 2010-2011, the rates of S. pneumoniae BSI and penicillin non-susceptibility decreased by 55% and 100%. In contrast the rate of group B streptococcal (GBS) BSI increased 34% over the same time period. GBS accounted for >80% of the recurrent infections following streptococcal BSI. Patients with breast cancer and those with soft-tissue/bone BSI sources were at increased risk for recurrent GBS infection but had lower rates of severe GBS disease. From 2000 to 2011, our comprehensive cancer center observed a significant decrease in the rates of S. pneumoniae BSI and a significant increase in the rates of GBS BSI.