Gagaletsios Lazaros A, Tagkalegkas Andreas, Bitar Ibrahim, Papagiannitsis Costas C
Department of Microbiology, University Hospital of Larissa, Larissa, Greece.
Department of Microbiology, Faculty of Medicine and University Hospital in Plzen, Charles University, Plzen, Czech Republic.
Mol Genet Genomics. 2025 May 26;300(1):52. doi: 10.1007/s00438-025-02258-2.
The objective of this study was to characterize the virulence characteristics of a collection of Klebsiella pneumoniae isolates collected from different clinical sources. A collection of 60 non-repetitive K. pneumoniae isolates, was studied. In vitro, virulence was analyzed by testing the survival of bacteria in pooled human serum. Isolates were typed by MLST. The genomes of 23 K. pneumoniae isolates, representatives of different STs and virulence profiles, were completely sequenced using the Illumina platform. Of note, 26/60 of K. pneumoniae isolates were resistant to killing by complement. Serum-resistant isolates belonged to distinct STs. Analysis of WGS data with VFDB showed the presence of several virulence genes related various virulence functions. Specifically, serum-resistant isolates carried a higher number of ORFs, which were associated with serum resistance, compared to serum-sensitive isolates. Additionally, analysis of WGS data showed the presence of multiple plasmid replicons that could be involved with the spread and acquisition of resistance and virulence genes. In conclusion, analysis of virulence characteristics showed that an important percentage (31.6%) of K. pneumoniae isolates were in vitro virulent by exhibiting resistance to serum. Thus, the presence of several virulence factors, in combination with the presence of multidrug resistance, could challenge antimicrobial therapy of infections caused by such bacteria.
本研究的目的是表征从不同临床来源收集的肺炎克雷伯菌分离株的毒力特征。研究了60株非重复性肺炎克雷伯菌分离株。在体外，通过检测细菌在混合人血清中的存活率来分析毒力。分离株通过多位点序列分型（MLST）进行分型。使用Illumina平台对23株肺炎克雷伯菌分离株（不同ST型和毒力谱的代表）的基因组进行了全测序。值得注意的是，60株肺炎克雷伯菌分离株中有26株对补体杀伤具有抗性。血清抗性分离株属于不同的ST型。利用VFDB对全基因组测序数据进行分析，结果显示存在多个与各种毒力功能相关的毒力基因。具体而言，与血清敏感分离株相比，血清抗性分离株携带更多与血清抗性相关的开放阅读框（ORF）。此外，对全基因组测序数据的分析表明存在多个质粒复制子，它们可能与耐药性和毒力基因的传播与获得有关。总之，毒力特征分析表明，相当比例（31.6%）的肺炎克雷伯菌分离株在体外具有毒力，表现为对血清具有抗性。因此，多种毒力因子的存在，再加上多重耐药性的存在，可能会给此类细菌引起的感染的抗菌治疗带来挑战。
