First Two Cases of Infected Aortic Aneurysm Caused by Non-Vaccine Streptococcus pneumoniae Serotype 23A

Dear Editor, Infected aortic aneurysm (IAA) is an uncommon, but life-threatening condition. Identification of the causative pathogen is essential for accurate diagnosis and effective treatment. However, 14–40% of IAA cases are culture-negative [1]. IAA due to Streptococcus pneumoniae is rare, and reports of the involvement of S. pneumoniae capsular serotypes and sequence types (STs) in IAA are even rarer [2-5]. We identified S. pneumoniae from culture-negative IAA by genetic analysis. To the best of our knowledge, as of 2019, only 59 cases of pneumococcal IAA have been reported in France, the United Kingdom (UK), the Netherlands, Germany, Switzerland, Belgium, Denmark, the United States (USA), Canada, Chile, Japan, Hong Kong, Korea, and Austria since 1977 [2-5]. In the previous cases of IAA due to S. pneumoniae, capsular serotype analysis was reported only for seven: 10A and 23F in the UK, 4 and 8 in Denmark, 19F in Hong Kong, 4 in Belgium, and 23 in USA [2-5]. We report the first two cases of culture-negative IAA due to non-vaccine S. pneumoniae serotype 23A, ST338. The study protocol was approved by the Institutional Ethics Committees of Tohoku University, Sendai, Japan (No. 2018-1-456). KCI Citation Count: 0