Bacteroides fragilis is the most common opportunistic anaerobic pathogen. In the absence of appropriate antimicrobial therapy, mortality rates associated with B. fragilis group infections can reach as high as 50%. Therefore, we aimed to elucidate the clinical characteristics and outcomes of B. fragilis infections and the molecular genetic characteristics of B. fragilis isolates. Forty B. fragilis clinical isolates were collected at Hanyang University Hospital between January 2022 and December 2023. Antimicrobial susceptibility was tested using the agar dilution method. Whole-genome sequencing was conducted using the Illumina platform (Illumina, San Diego, CA, USA). Various multilocus sequence types of B. fragilis were identified, including ST149 (N=4), ST11 (N=4), ST1 (N=3), ST21 (N=2), and ST157 (N=1). The insertion sequence (IS) IS1187, located upstream of cfiA, was associated with high-level carbapenem resistance in the ST157 isolate. B. fragilis toxin genes (bft ) were identified in 30% of isolates. The most common comorbidities were diabetes mellitus (26.5%) and non-metastatic cancer (23.5%). Five patients (14.7%) died within 30 days, and two (5.9%) deaths were directly attributable to B. fragilis infection. The emergence of high-level MIC carbapenem-resistant B. fragilis ST157 has led to caution in the presence of B. fragilis infections.

中文翻译：

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脆弱拟杆菌感染的临床结果和分子特征。


脆弱拟杆菌是最常见的机会性厌氧病原体。在没有适当的抗菌治疗的情况下，与脆弱芽孢杆菌组感染相关的死亡率可高达 50%。因此，我们旨在阐明脆弱芽孢杆菌感染的临床特征和结果以及脆弱芽孢杆菌分离株的分子遗传学特征。2022 年 1 月至 2023 年 12 月期间，汉阳大学医院收集了 40 例脆弱芽孢杆菌临床分离株。使用琼脂稀释法测试抗菌药物敏感性。使用 Illumina 平台 （Illumina， San Diego， CA， USA） 进行全基因组测序。鉴定出脆弱双歧杆菌的多种多位点序列类型，包括 ST149 （N=4）、ST11 （N=4）、ST1 （N=3）、ST21 （N=2） 和 ST157 （N=1）。插入序列 （IS） IS1187 位于 cfiA 的上游，与 ST157 分离株中的高水平碳青霉烯类耐药性相关。在 30% 的分离株中鉴定出脆弱芽孢杆菌毒素基因 （bft）。最常见的合并症是糖尿病 （26.5%） 和非转移性癌症 （23.5%）。5 例患者 （14.7%） 在 30 天内死亡，2 例 （5.9%） 死亡直接归因于脆弱芽孢杆菌感染。高水平 MIC 碳青霉烯类耐药的脆弱双歧杆菌 ST157 的出现导致在存在脆弱双歧杆菌感染时需要谨慎。