Prolonged hospitalization (>2 weeks)
Previous intravenous antibiotic exposure during current hospitalization.
Severe illness (hypotension, hypoxia requiring intubation, HAP requiring transfer to critical care unit)
Currently admitted in critical care unit
Known colonization or recent infection with Pseudomonas aeruginosa
Known colonization or recent infection with piperacillin-tazobactam resistant Pseudomonas aeruginosa or ESBL-producing organism