[Frequency of extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase genes in Escherichia coli and Klebsiella pneumoniae over a three-year period in a University Hospital in Korea].

[Frequency of extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase genes in Escherichia coli and Klebsiella pneumoniae over a three-year period in a University Hospital in Korea].