A 51‐year‐old man with Guillain‐Barré syndrome developed a dissecting vertebral artery aneurysm. Initial magnetic resonance angiography showed no abnormality, including dissecting aneurysm of the bilateral vertebral arteries. He developed subarachnoid hemorrhage. Radiological examination revealed bilateral dissecting vertebral artery aneurysms. The left ruptured dissecting vertebral artery aneurysm was treated by stent‐assisted coil embolization with preservation of the affected vertebral artery. Although it is rare, there is a possibility that dissection of the intracranial artery might occur in a patient with Guillain‐Barré syndrome in a short period of time. The dissecting aneurysm might be formed by external force to the vertebral artery, and the aneurysm might subsequently rupture due to hypertension.

For a case of dissecting vertebral artery aneurysm (DVAA) in a dominant vertebral artery (VA) or posterior inferior cerebellar artery (PICA)-involving lesion, stent-assisted coil embolization (SACE) is an effective technique to preserve blood flow of the VA. A 41-year-old man presented with subarachnoid hemorrhage. Angiography demonstrated DVAA on the left VA just distal to the PICA, and the right VA was thinner than the left. For this case, SACE was performed to preserve the left VA and PICA. On the 10th day, angiography showed recurrence of the dissection. The dissected portion had thickened and extended to both distal and proximal sides involving the PICA origin and proximal portion to the PICA. A second endovascular embolization was performed and the recurrent dissecting aneurysm was embolized including the main VA cavity. In cases of DVAA, there is a possibility of recurrence after SACE, if a dissecting cavity remains unembolized. Therefore, total embolization is necessary under close observation from multiple angles, including the down-the-barrel view.

Background Japan is one of the hypervirulent Klebsiella pneumoniae (hvKp) endemic areas, resulting in an alarming issue in actual clinical settings. However, little is known regarding key virulence factors responsible for hvKp infection. Methods We analyzed K. pneumoniae isolates collected between 2017 and 2019, and defined hvKp as a pyogenic infection. Classical K. pneumoniae (cKp) involved a non-invasive infection or uncomplicated bacteremia. Isolates belonging to the K. pneumoniae species complex were excluded. Results We analyzed 112 isolates, including 19 hvKp, 67 cKp, and 26 colonizers, by whole-genome sequencing. Population genomics revealed that the K1-sequence type (ST) 82 clade was distinct from that of K1-ST23 clone (Figure 1). The virulence-gene profiles also differed between K1-ST82 (aerobactin and rmpA) and K1-ST23 (aerobactin, yersiniabactin, salmochelin, colibactin, and rmpA/rmpA2). The K2 genotype was more diverse than that of K1. A neighboring subclade of K1-ST23 (comprising ST29, ST412, ST36, and ST268) showed multidrug-resistance and hypervirulence potentials. Logistic-regression analysis revealed that diabetes mellitus was associated with K. pneumoniae infection (odds ratio [OR]: 4.11; 95% confidence interval [CI]: 1.14–14.8). No significant association was found between hvKp diagnosis and clinical characteristics, such as diabetes mellitus or community acquisition (Table 1). The K1 genotype (OR: 9.02; 95% CI: 2.49–32.7; positive-likelihood ratio [LR]: 4.08), rmpA (OR: 8.26; 95% CI: 1.77–38.5; positive LR: 5.83), and aerobactin (OR: 4.59; 95% CI: 1.22–17.2; positive LR: 3.49) were substantial diagnostic predictors of hvKp (Table 2). Figure 1. Phylogenetic distribution of genetic virulence factors in 112 K. pneumoniae isolates The highlighted strains are clinically pathogenic (orange, hypervirulent K. pneumoniae; yellow, classical K. pneumoniae; sky blue, colonization). The non-highlighted strain (NTUH-K2044) is a reference K. pneumoniae strain. Conclusion In hvKp-rich settings, diabetes mellitus, community-acquisition, and siderophores other than aerobactin were not remarkable predictors of hvKp infection. However, the K1 genotype, rmpA, and aerobactin were found to be substantial predictors, warranting clinical assessment of any possible/further pyogenic (metastatic) infection. We believe that these findings shed light on key hvKp virulence factors. Disclosures All Authors: No reported disclosures