Purpose: To  drive decisions on antibiotic therapy in the intensive care unit (ICU),  we developed an antibiotic care bundle (ABC-Bundle) with evidence-based  recommendations (EBRs) for antibiotic prescriptions.

Methods: We  conducted a three-step prospective study. First, a systematic review  was performed of the literature reporting EBRs for antibiotic usage in  the ICU. Second, we developed an ABC-Bundle through a two-round,  RAND-modified Delphi method with an international expert panel,  including the most relevant EBRs on a 9-point Likert scale. Those EBRs  that were considered mandatory by >50% of the experts were included  in the bundle. Third, we assessed the adherence to and applicability of  the bundle in two mixed university ICUs.

Results: Out  of 1190 potentially relevant articles, 14 (four guidelines, four  randomised controlled trials and six systematic reviews) fulfilled the  eligibility criteria. Six EBRs were classified as relevant: 1. Provide  rationale for antibiotic start; 2. Perform appropriate microbiological  sampling; 3. Prescribe empirical antibiotic therapy according to  guidelines (Day 1); 4. Review diagnosis; 5. Evaluate de-escalation based  on microbiological results (Days 2-5); and 6. Consider discontinuation  of treatment (Days 3-5). Daily adherence to the ABC-Bundle,  prospectively assessed in 861 days of therapy in 142 ICU patients,  ranged from 2% to 37%.

Conclusion: The ABC-Bundle  is a novel tool to improve delivery of appropriate antibiotic therapy  to ICU patients. The low adherence in the prospective cohorts confirms  the significant role that the ABC-Bundle could play in an antibiotic  stewardship programme in the ICU setting.

Keywords: Antibiotic prescription; Antimicrobial resistance; Antimicrobial therapy; Care bundle; ICU; Infectious diseases.