PDF(Pubmed)
Abstract：
UNASSIGNED: Convergence of Klebsiella pneumoniae (KP) pathotypes has been increasingly reported in recent years. These pathogens combine features of both multidrug-resistant and hypervirulent KP. However, clinically used indicators for hypervirulent KP identification, such as hypermucoviscosity, appear to be differentially expressed in convergent KP, potential outbreak clones are difficult to identify. We aimed to fill such knowledge gaps by investigating the temperature dependence of hypermucoviscosity and virulence in a convergent KP strain isolated during a clonal outbreak and belonging to the high-risk sequence type (ST)307.
UNASSIGNED: Hypermucoviscosity, biofilm formation, and mortality rates in Galleria mellonella larvae were examined at different temperatures (room temperature, 28°C, 37°C, 40°C and 42°C) and with various phenotypic experiments including electron microscopy. The underlying mechanisms of the phenotypic changes were explored via qPCR analysis to evaluate plasmid copy numbers, and transcriptomics.
UNASSIGNED: Our results show a temperature-dependent switch above 37°C towards a hypermucoviscous phenotype, consistent with increased biofilm formation and in vivo mortality, possibly reflecting a bacterial response to fever-like conditions. Furthermore, we observed an increase in plasmid copy number for a hybrid plasmid harboring carbapenemase and rmpA genes. However, transcriptomic analysis revealed no changes in rmpA expression at higher temperatures, suggesting alternative regulatory pathways.
UNASSIGNED: This study not only elucidates the impact of elevated temperatures on hypermucoviscosity and virulence in convergent KP but also sheds light on previously unrecognized aspects of its adaptive behavior, underscoring its resilience to changing environments.
UNASSIGNED: Hypermucoviscosity, biofilm formation, and mortality rates in Galleria mellonella larvae were examined at different temperatures (room temperature, 28°C, 37°C, 40°C and 42°C) and with various phenotypic experiments including electron microscopy. The underlying mechanisms of the phenotypic changes were explored via qPCR analysis to evaluate plasmid copy numbers, and transcriptomics.
UNASSIGNED: Our results show a temperature-dependent switch above 37°C towards a hypermucoviscous phenotype, consistent with increased biofilm formation and in vivo mortality, possibly reflecting a bacterial response to fever-like conditions. Furthermore, we observed an increase in plasmid copy number for a hybrid plasmid harboring carbapenemase and rmpA genes. However, transcriptomic analysis revealed no changes in rmpA expression at higher temperatures, suggesting alternative regulatory pathways.
UNASSIGNED: This study not only elucidates the impact of elevated temperatures on hypermucoviscosity and virulence in convergent KP but also sheds light on previously unrecognized aspects of its adaptive behavior, underscoring its resilience to changing environments.
摘要：
■近年来，肺炎克雷伯菌（KP）致病型的趋同性报道越来越多。这些病原体结合了多重耐药和高毒力KP的特征。然而,临床使用的高毒力KP鉴定指标，例如高粘膜粘度，似乎在收敛的KP中差异表达，潜在的爆发克隆很难识别。我们旨在通过研究在克隆爆发期间分离出的属于高风险序列类型（ST）307的会聚KP菌株中高粘膜粘度和毒力的温度依赖性来填补这些知识空白。
■高粘膜粘度，生物膜的形成，和死亡率在不同温度下检查了Galleriamelonella幼虫（室温，28°C,37°C,40°C和42°C）以及包括电子显微镜在内的各种表型实验。通过qPCR分析探索表型变化的潜在机制，以评估质粒拷贝数，和转录组学。
■我们的结果表明，高于37°C的温度依赖性转变为高粘膜粘性表型，与增加的生物膜形成和体内死亡率一致，可能反映了细菌对发热样疾病的反应。此外，我们观察到含有碳青霉烯酶和rmpA基因的杂交质粒的质粒拷贝数增加。然而,转录组学分析显示在较高温度下rmpA表达没有变化，建议替代调节途径。
■这项研究不仅阐明了高温对会聚KP中的高粘膜粘度和毒力的影响，而且还阐明了其适应行为的先前未被认识到的方面，强调其对不断变化的环境的适应能力。
■高粘膜粘度，生物膜的形成，和死亡率在不同温度下检查了Galleriamelonella幼虫（室温，28°C,37°C,40°C和42°C）以及包括电子显微镜在内的各种表型实验。通过qPCR分析探索表型变化的潜在机制，以评估质粒拷贝数，和转录组学。
■我们的结果表明，高于37°C的温度依赖性转变为高粘膜粘性表型，与增加的生物膜形成和体内死亡率一致，可能反映了细菌对发热样疾病的反应。此外，我们观察到含有碳青霉烯酶和rmpA基因的杂交质粒的质粒拷贝数增加。然而,转录组学分析显示在较高温度下rmpA表达没有变化，建议替代调节途径。
■这项研究不仅阐明了高温对会聚KP中的高粘膜粘度和毒力的影响，而且还阐明了其适应行为的先前未被认识到的方面，强调其对不断变化的环境的适应能力。
