Oh Man Hwan, Kim Nayeong, Islam Md Minarul, Kim Seong Yeob, Lee Da Eun, Kim Yu Kyung, Kwon Ki Tae, Lee Je Chul
Department of Microbiology, College of Science and Technology, Dankook University, Cheonan, South Korea; Center for Bio-Medical Engineering Core Facility, Dankook University, Cheonan, South Korea; Smart Animal Bio Institute, Dankook University, Cheonan, South Korea.
Department of Microbiology, School of Medicine, Kyungpook National University, Daegu, South Korea; Untreatable Infectious Disease Institute, Kyungpook National University, Daegu, South Korea.
Microb Pathog. 2025 Jan;198:107118. doi: 10.1016/j.micpath.2024.107118. Epub 2024 Nov 15.
Multi-drug resistant Acinetobacter baumannii poses a significant threat to public health. This study investigated the genomic features and phenotypic characteristics of two clinical A. baumannii strains, KBN10P01317 (low-virulent) and KBN10P01599 (high-virulent), which share the same sequence type and antimicrobial susceptibility profile. The phenotypic characteristics of A. baumannii strains were assessed by antimicrobial susceptibility testing and virulence trait examination in vitro and in vivo. Whole-genome sequencing was conducted for comparative genomic analysis, and the expression of virulence-associated genes was analyzed using quantitative polymerase chain reaction. Our comparative genomic analysis revealed that KBN10P01599 harbored a larger genome with a greater number of antimicrobial resistance genes, including two copies of the critical resistance gene bla, which might contribute to its higher minimum inhibitory concentration for carbapenems (64 μg/ml) compared to KBN10P01317 (32 μg/ml). Although both A. baumannii strains possessed the same repertoire of virulence-associated genes, KBN10P01599 exhibited significantly enhanced expression of quorum sensing (abaI/R) and biofilm formation genes (csuCDE, bap, and pgaA), correlating with its virulence traits, including increased surface motility, biofilm formation, and adherence to host cells. The differences in the expression of virulence-associated genes between the two strains were partly attributed to the transposition of insertion sequence elements. These findings provide valuable insights into the genetic basis of the virulence potential and antimicrobial resistance in A. baumannii, highlighting the evolutionary changes that may occur within strains of the same clone.
多重耐药鲍曼不动杆菌对公众健康构成重大威胁。本研究调查了两株临床鲍曼不动杆菌菌株KBN10P01317（低毒力）和KBN10P01599（高毒力）的基因组特征和表型特征，这两株菌具有相同的序列类型和抗菌药物敏感性谱。通过体外和体内抗菌药物敏感性测试及毒力特性检测来评估鲍曼不动杆菌菌株的表型特征。进行全基因组测序以进行比较基因组分析，并使用定量聚合酶链反应分析毒力相关基因的表达。我们的比较基因组分析表明，KBN10P01599拥有更大的基因组，含有更多的抗菌耐药基因，包括关键耐药基因bla的两个拷贝，这可能导致其对碳青霉烯类药物的最低抑菌浓度（64μg/ml）高于KBN10P01317（32μg/ml）。尽管两株鲍曼不动杆菌都拥有相同的毒力相关基因库，但KBN10P01599的群体感应（abaI/R）和生物膜形成基因（csuCDE、bap和pgaA）的表达显著增强，这与其毒力特性相关，包括表面运动性增加、生物膜形成以及对宿主细胞的黏附。两株菌株之间毒力相关基因表达的差异部分归因于插入序列元件的转座。这些发现为鲍曼不动杆菌毒力潜力和抗菌耐药性的遗传基础提供了有价值的见解，突出了同一克隆菌株内可能发生的进化变化。
