Scanning electron microscopy images of Klebsiella pneumoniae
isolates in the absence of treatment (A–E, control) and in the presence
of polymyxin B (PMB) alone at 0.5 mg/L (A–E, polymyxin B), meropenem
alone at 20 mg/L (A–E, meropenem) and PMB in combination with meropenem
(A–E, combination). Magnification at 50,000× with the scale bar
set at 300 nm to image individual bacteria of (A) BRKP20 (PMB MIC <0.5 mg/L,
meropenem MIC = 16 mg/L); (B) BRKP21 (PMB MIC = 0.5 mg/L,
meropenem MIC = 16 mg/L); (C) BRKP27 (PMB MIC = 1 mg/L,
meropenem MIC = 16 mg/L); (D) BRKP67 (PMB MIC = 8 mg/L,
meropenem MIC = 64 mg/L); and (E) BRKP28 (PMB MIC >128 mg/ L,
meropenem MIC = 256 mg/L).