Should Anti-Anaerobic Antibiotics Be Avoided in Critically Ill Patients?

The anaerobic gut flora has important protective properties that may be depleted by antibiotics with anaerobic activity, thereby allowing proliferation of bacteria capable of causing opportunistic infections. Is this effect clinically relevant in critically ill patients? Researchers at one U.S. center conducted a retrospective observational cohort study of 3032 critically ill patients, all of whom received parenteral antibiotics within 72 hours of mechanical ventilation. The primary outcome was ventilator-associated pneumonia [VAP]–free survival.

In multivariate adjusted analysis, use of anti-anaerobic antibiotics was significantly associated with decreased VAP-free survival (hazard ratio, 1.24), infection-free survival (HR, 1.22), and overa…