Bacteraemia incidence, causative organisms and resistance patterns, antibiotic strategies and outcomes in a single university hospital ICU: continuing improvement between 2000 and 2013

Abstract

Objectives: The optimal duration of antibiotic treatment in patients with bloodstream infections remains contentious, with concerns regarding both undertreatment and the encouragement of antibiotic resistance. In our ICU we traditionally use short-course antibiotic monotherapy as the mainstay of treatment. We sought to document the impact of this strategy on pathogen type, resistance patterns and patient outcomes. A comparison was made against data collected during a similar exercise in 2000.

Methods: We retrospectively reviewed data on all patients with community-, hospital- and ICU-acquired bacteraemia over a 6 month period (1 December 2012 to 31 May 2013) in a general medical-surgical ICU in a London university hospital. Causative pathogens, resistance patterns, use and duration of monotherapy or combination therapy, breakthrough and relapse rates, and patient outcomes were assessed.

Results: The 2013 cohort comprised 113 episodes in 87 patients. Short-course monotherapy (median course 4-5 days) was used in 65.7% of episodes (73.5% in 2000). As with the 2000 cohort, the incidence of antimicrobial resistance, fungaemia, bacteraemia breakthrough and relapse remained low. Of note, there was a decreasing incidence of ICU-acquired MRSA, MDR Gram-negative bacteraemia and fluconazole-resistant candidaemia. Hospital mortality was 32% (45% in 2000).

Conclusions: Our strategy predominantly utilizing short-course antibiotic monotherapy remains effective in achieving good clinical outcomes among patients with bloodstream infections, with low rates of antibiotic resistance and clinical relapse. Prospective trials of short-course monotherapy are warranted to assess clinical efficacy and antimicrobial resistance.

Keywords: antibiotic combination therapy; antibiotic duration; antibiotic monotherapy; antibiotic resistance; fungaemia; intensive care; mortality.