Ultrastructural Changes in Clinical and Microbiota Isolates of Klebsiella pneumoniae Carriers of Genes bla_SHV, bla_TEM, bla_CTX-M, or bla_KPC When Subject to β-Lactam Antibiotics

Figure 1

(a–e) Transmission electron micrographs of isolate K3C from K. pneumoniae. (a) bacterial cell without treatment (control)—preserved morphology, cytoplasmic membrane (arrow), cell wall (w), and cytoplasm (C) intact. (b-c) Cells subjected to CTX (64 μg mL⁻¹)—decreased cytoplasmic material (C), presence of membrane compartments (stars), electron-lucent spaces (asterisks) and disorganization of the membrane and cell wall. (d) Cell subjected to CAZ (32 μg mL⁻¹)—elongated aspect morphology with loss of cytoplasmic material (C) and the presence of small membrane compartments (stars). (e) Cell subjected to ATM (32 μg mL⁻¹)—normal morphology in the presence of electron-lucent spaces (asterisks) in the cytoplasm (C). Bars = 0.5 μm. CAZ: ceftazidime; CTX: cefotaxime; and ATM: aztreonam.

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