Empiric Antibiotics in Critical Illness: Do they Help or Harm?

Empiric antibiotic therapy — the administration of antibiotics before a microbiological diagnosis of infection is established — is a widely-used, but unproven practice in contemporary intensive care units (ICUs). The perceived need for pre-emptive antibiotic therapy stems from factors unique to infection in the critically ill. Nosocomial infection is common, occurring in up to one third of all patients admitted to an ICU [1]. The diagnosis is challenging. Clinical manifestations are non-specific [2–5], culture data are unreliable because of concomitant antibiotic use [6], and the differentiation of colonization from invasive infection is notoriously difficult [7, 8]. Infecting organisms are commonly resistant to first-line antibiotics [9, 10]. ICU-acquired infections develop in the sickest patients, for whom maximal therapeutic intervention is the norm, and clinicians are frequently reluctant to stop therapy, even when cultures are negative [11, 12].