Antibiotic Failure: Apparent or Actual in the Critical Care Unit

Abstract

This chapter reviews the clinical approach to persistent fever as a manifestation of apparent or vertical antibiotic failure in the CCU. The clinical presentation is either that of persistent fever while on antimicrobial therapy or new fevers while in the CCU. Unfortunately, there are many causes of fevers in the CCU due to infectious as well as non-infectious causes. For many practitioners, continued fever suggests antibiotic treatment failure and new fever suggests a new infectious process. Sustained or new fevers are often accompanied by leukocytosis. As with fever, leukocytosis may be due to non-infectious or infectious causes and is not, per se, indicative of an infectious etiology, e.g., leukocytosis in patients on steroids. Since leukocytosis is reflective of stress due to any cause, most cases of leukocytosis with a left shift are due to non-infectious events/causes of fever. True antibiotic failure is usually due to incorrect spectrum or a tissue penetration problem but not antibiotic-resistant drug therapy.