The use of “double coverage” (two antibiotics used to provide coverage for the same organism) is based upon the following assumptions:
Contemporary data do not support the use of “double coverage” for the latter two indications.
Inappropriate initial therapy has been shown to cause increased morbidity and mortality, specifically related to Gram-negative infections (usually Pseudomonas and Acinetobacter spp.).
Thus, double coverage serves the purpose of providing broad spectrum initial empiric coverage until susceptibility data are known.
However, once susceptibility data are known, double coverage does not need to be continued.
No evidence exists to support the superiority of combination therapy over monotherapy for Gram negative infections once susceptibilities are known.
Thus, once culture identification and susceptibilities have been reported, de-escalation to a single agent is strongly recommended.