Fatal Pneumocephalus Caused by Hypervirulent Klebsiella pneumoniae, Germany

Abstract

We report a fatal case of pneumocephalus in Germany caused by hypervirulent Klebsiella pneumoniae sequence type 23, confirmed by using clinical, histopathologic, and genomic analyses. The patient reported no travel history, suggesting local emergence. This unusual case reveals an unclear pathogen prevalence and demonstrates the need for increased awareness of global spread.

Keywords: Germany; Klebsiella pneumoniae; Pneumocephalus; bacteria; bacterial infection; emerging disease; hypervirulent; meningitis/encephalitis.

Figure 1

Radiologic and pathologic findings from a fatal pneumocephalus case caused by hypervirulent Klebsiella pneumoniae in Germany. A) Computed tomography imaging of the neurocranium revealing gas inclusions both in the arterial and venous system and the inner and outer cerebrospinal fluid spaces consistent with an intravital pneumocephalus. B) Postmortem coronal brain section revealing infiltrates of the leptomeninges and signs of global hypoxic-ischemic brain damage including blurred demarcation between the white and gray matter and discoloration. C) Microscopic appearance of purulent meningitis with bacilli accumulating in the leptomeninges. Hematoxylin and eosin stain. Scale bar indicates 50 µm.

Figure 2

Minimum spanning tree generated to evaluate the genetic relationship of 29 Klebsiella pneumoniae-ST23 isolates (capsule types K1 and K57) during study of a fatal pneumocephalus case caused by hypervirulent K. pneumoniae in Germany (Appendix Table). Ridom SeqSphere version 10.0.4 (ridom, https://www.ridom.de) was used to create tree for 29 samples isolated from hospitals in Germany on the basis of 2,358 columns, pairwise ignoring missing values, and logarithmic scale. Distance is on the basis of columns from K. pneumoniae sensu lato core genome multilocus sequence type (2,358 genes). Cluster distance threshold is 15 according to the Ridom Seqsphere. The patient isolates from this case (0354/24 and 0355/24) are labeled as cluster 2. Isolate 0074/24 is another K. pneumoniae ST23-K1 isolate from a patient with liver abscess admitted to the same hospital. Cluster 1 represents K. pneumoniae ST23-K57 isolates with virulence or convergence plasmids that were in part from patients previously hospitalized in Ukraine (3,4). ST, sequence type.

Figure 3

Comparative plasmid alignment of hypervirulent Klebsiella pneumoniae from the study of a fatal pneumocephalus case in Germany, completed by using BRIG (10). The innermost rings show guanine-cytosine content, and the outer ring shows the used reference virulence plasmid pK2044 (blue) from K. pneumoniae strain NTUH-K2044 from Taiwan (11). Concentric rings illustrate the virulence plasmids of the K. pneumoniae isolates from this case, 0354/24 (light green) and 0355/24 (dark green), and a patient isolate from the same hospital, 0074/24 (orange). Sequence similarity to the reference plasmid is indicated by the intensity and continuity of the colored rings. The gaps correspond to regions with no major sequence similarity. The locations of the typical virulence-associated genes (iucA, iroB, rmpA, rmpA2, peg344) (12) are visualized on the outermost ring.