Guembe María, Hafian Rama, Díaz-Navarro Marta, Visedo Andrés, De Maio Flavio, Pimpinelli Fulvia, Cavallo Ilaria, Truglio Mauro, Sivori Francesca, Di Domenico Enea Gino
Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
IiSGM, Madrid, Spain.
Microbiol Spectr. 2025 Feb 4;13(2):e0221524. doi: 10.1128/spectrum.02215-24. Epub 2025 Jan 13.
is a significant healthcare-associated pathogen, notable for its diverse virulence and antibiotic resistance profiles. This study aimed to characterize the genotypic and phenotypic diversity of isolates and evaluate their virulence using the model. Biomass production, metabolic activity, capsule formation, and siderophore production were assessed in 27 . isolates from hospital-associated infections. Lethality curves were generated using the model, with survival monitored hourly from 16 to 48 hours. The most common sequence types (ST) identified were the high-risk clones ST307 ( = 10), ST512 ( = 8), ST101 ( = 7), and ST661 ( = 2). These STs were associated with distinct K-locus, including KL102, KL107, KL17, and KL39. Most isolates belonged to the O2afg locus ( = 18), with the carbapenemase genotype detected in 96.3% of strains. None of the isolates were classified as hypervirulent. Phenotypically, ST661 exhibited the highest biomass production despite showing similar metabolic activity to other STs. A positive correlation was observed between biomass and siderophore production, while capsule production was inversely correlated with biomass. In the model, ST661 demonstrated the highest virulence, resulting in 100% mortality by 48 hours, compared to survival rates of 21.4% for ST101, 38.0% for ST307, and 31.2% for ST512. These findings underscore the pathogenic potential of ST661 isolates with enhanced biofilm production. The model may serve as an effective system for evaluating the virulence of emerging lineages.IMPORTANCEWe demonstrate that the model is a useful tool to analyze the virulence of carbapenem-resistant strains. Our findings highlight the pathogenicity of carbapenem-resistant isolates, particularly the role of the ST661 that, despite being a rare lineage, harbors the blaVIM gene and is associated with high biofilm production and the highest mortality rates.
是一种重要的医疗保健相关病原体，以其多样的毒力和抗生素耐药谱而闻名。本研究旨在表征分离株的基因型和表型多样性，并使用该模型评估其毒力。在27株医院相关感染的分离株中评估了生物量产生、代谢活性、荚膜形成和铁载体产生。使用该模型生成致死率曲线，从16小时到48小时每小时监测存活率。鉴定出的最常见序列类型（ST）是高风险克隆ST307（n = 10）、ST512（n = 8）、ST101（n = 7）和ST661（n = 2）。这些ST与不同的K位点相关，包括KL102、KL107、KL17和KL39。大多数分离株属于O2afg位点（n = 18），96.3%的菌株检测到碳青霉烯酶基因型。没有分离株被分类为高毒力株。表型上，ST661尽管与其他ST表现出相似的代谢活性，但生物量产生最高。观察到生物量与铁载体产生之间呈正相关，而荚膜产生与生物量呈负相关。在该模型中，ST661表现出最高的毒力，到48小时时导致100%的死亡率，相比之下，ST101的存活率为21.4%，ST307为38.0%，ST512为31.2%。这些发现强调了具有增强生物膜产生的ST661分离株的致病潜力。该模型可作为评估新兴谱系毒力的有效系统。重要性我们证明该模型是分析耐碳青霉烯菌株毒力的有用工具。我们的发现突出了耐碳青霉烯分离株的致病性，特别是ST661的作用，尽管它是一个罕见的谱系，但携带blaVIM基因，与高生物膜产生和最高死亡率相关。
