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 3

(a–h) Transmission electron micrographs of isolate K652 of K. pneumoniae. (a) Untreated bacterial cell—cell wall with preserved morphology (w) and cytoplasm (C) intact, besides regular septation (arrowheads). (b-c) Cell subjected to CTX (98 μg mL⁻¹)—presence of cells not grown and rounded (stars) at the ends of cells with normal morphology. (d–f) Cells subjected to CAZ (27 μg mL⁻¹)—consecutive formation of septa (arrowheads) providing elongation of bacterial morphology. Observe disorganization of membrane and cell wall with elastic aspect. (g-h) Cell subjected to IMP (16 μg mL⁻¹)—morphology of elongated appearance with formation of consecutive septa (arrowheads). Bars = 0.5 μm. CAZ: ceftazidime; CTX: cefotaxime; and IMP: imipenem.