Bacterial strains
Three strains of β-lactamase-producing Klebsiella pneumoniaelisted in Table 1 were used in this study. K. pneumoniae ATCC
BAA-2473 was obtained from American Type Culture Collection. Clinical
isolates (K. pneumoniae MSC 21664 and MSC 21444) were provided by
Meiji Seika Pharma Co., Ltd.