Introduction
Klebsiella pneumoniae is one of the most common nosocomial bloodstream infection (BSI) pathogens in neonatal intensive care units (NICUs) of developing countries. Its ability to produce extended-spectrum beta-lactamases (ESBLs) has caused great concern worldwide. Early studies reported that high beta-lactam antibiotic consumption was an independent risk factor for acquisition of ESBL-producing K. pneumoniae BSI.