Li Liang, Yeaman Michael R, Bayer Arnold S, Xiong Yan Q
Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA.
David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
Antibiotics (Basel). 2019 May 29;8(2):71. doi: 10.3390/antibiotics8020071.
Persistent methicillin-resistant (MRSA) bacteremia (PB) represents an important subset of infection and correlates with poor clinical outcomes. MRSA isolates from patients with PB differ significantly from those of resolving bacteremia (RB) with regard to several in vitro phenotypic and genotypic profiles. For instance, PB strains exhibit less susceptibility to cationic host defense peptides and vancomycin (VAN) killing under in vivo-like conditions, greater damage to endothelial cells, thicker biofilm formation, altered growth rates, early activation of many global virulence regulons (e.g., , , and ) and higher expression of purine biosynthesis genes (e.g., ) than RB strains. Importantly, PB strains are significantly more resistant to VAN treatment in experimental infective endocarditis as compared to RB strains, despite similar VAN minimum inhibitory concentrations (MICs) in vitro. Here, we review relevant phenotypic and genotypic characteristics related to the PB outcome. These and future insights may improve our understanding of the specific mechanism(s) contributing to the PB outcome, and aid in the development of novel therapeutic and preventative measures against this life-threatening infection.
持续性耐甲氧西林金黄色葡萄球菌(MRSA)菌血症(PB)是感染的一个重要亚组,与不良临床结局相关。从PB患者分离出的MRSA菌株在几种体外表型和基因型特征方面与菌血症缓解(RB)患者的菌株有显著差异。例如,在类似体内的条件下,PB菌株对阳离子宿主防御肽和万古霉素(VAN)杀伤的敏感性较低,对内皮细胞的损伤更大,生物膜形成更厚,生长速率改变,许多全局毒力调节子(如 、 、 和 )早期激活,嘌呤生物合成基因(如 )的表达高于RB菌株。重要的是,尽管PB菌株和RB菌株在体外的VAN最低抑菌浓度(MIC)相似,但在实验性感染性心内膜炎中,PB菌株对VAN治疗的耐药性明显高于RB菌株。在此,我们综述与PB结局相关的表型和基因型特征。这些以及未来的见解可能会增进我们对导致PB结局的具体机制的理解,并有助于开发针对这种危及生命感染的新型治疗和预防措施。