Absence of microbial adaptation to taurolidine in patients on home parenteral nutrition who develop catheter related bloodstream infections and use taurolidine locks

Abstract

Some home parenteral nutrition (HPN) patients develop catheter related bloodstream infections (CRBSI) despite using an anti-microbial catheter lock solution taurolidine. The aim of this study was to assess whether long-term use of taurolidine leads to selective growth of microorganisms with increased taurolidine minimum inhibitory concentrations (MICs). Bloodstream infections among 158 HPN patients with long-term taurolidine catheter locking were analyzed retrospectively. CRBSI-diagnosis was based on clinical symptoms, culture results, and absence of other sources of infections. CRBSIs were classified as definitive, probable or possible and exit site/tunnel/port or luminal infections. MICs were determined by broth microdilution. Between January 2009 and April 2011, 14 patients developed at least one luminal CRBSI episode during long-term taurolidine catheter locking (median (range) = 451 (78-1394) days). Coagulase-negative Staphylococcus species or Staphylococcus aureus predominated among CRBSI-causing Gram-positive bacteria. Taurolidine MICs were 512 mg/l or less in 50% of these isolates (MIC50). Taurolidine MIC50 for Klebsiella pneumoniae and Escherichia coli, the most common CRBSI-causing Gram-negative bacteria, were 256 and 512 mg/l, respectively. Taurolidine MIC50 among CRBSI-causing Candida albicans were 2048 mg/l. Adaptation of microorganisms to taurolidine has not yet emerged as a factor in the pathogenesis of CRBSI in HPN patients with long-term taurolidine catheter locking.