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

Abstract

Objectives: To determine the comparative rates, clinical characteristics, and outcomes of invasive infections due to specific streptococcal types in patients with cancer.

Methods: 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.

Results: 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.

Conclusions: 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.