Lamy Brigitte, Laurent Frédéric, Simoes Da Silva Carolina J, Wadhawan Ashima, Ledger Elizabeth V K, Kolenda Camille, Martins Simoes Patricia, Edwards Andrew M, Dionne Marc S
Hôpitaux Universitaires Paris Seine Saint-Denis, APHP, Université Sorbonne Paris Nord, Villetaneuse, France.
Infection Antimicrobials Modelling Evolution (IAME), INSERM, Paris, France.
Infect Immun. 2025 Jun 10;93(6):e0059424. doi: 10.1128/iai.00594-24. Epub 2025 May 23.
can acquire antimicrobial resistance, which in turn may affect its pathogenic potential. Using a panel of paired clinical isolates collected before and after daptomycin resistance acquisition, most frequently through a single mutation, we show a relationship between increasing daptomycin minimum inhibitory concentration and reduced virulence in a systemic infection model. Analyzing toxin production, bacterial growth characteristics, and cell surface properties, we failed to link daptomycin resistance-related attenuated virulence to either reduced virulence factor production, reduced fitness, or any of the cell surface characteristics investigated. Competition assays in also did not support any altered ability in immune evasion. Instead, using a panel of mutant flies defective for various immune components, we show that this daptomycin resistance-related attenuated virulence is mostly explained by greater susceptibility to the activity of prophenoloxidase, a tyrosinase involved in melanization, but not to antimicrobial peptides or Bomanin antimicrobial effectors. Further investigation could not link daptomycin resistance-related attenuation of virulence to differential susceptibility to reactive oxygen species or quinones prominently associated with phenoloxidase bacterial-killing activity. Taken together, it appears that daptomycin resistance attenuates virulence through enhanced sensitivity to phenoloxidase based on a complex mechanism. Our study provides new insights into the understanding of the crosstalk between antimicrobial resistance, escape from immune killing, and virulence.IMPORTANCEThis study advances current knowledge in the field of host-microbe interactions and antimicrobial resistance by exploring crosstalk between antimicrobial resistance and virulence. It shows how acquiring antimicrobial resistance can alter bacterial virulence and helps shape virulence. Relative to the parental staphylococcal strain, daptomycin-resistant clinical isolates most often varied by one single mutation in a gene involved in the composition of the bacterial membrane, and these strains were much less virulent when fruit flies were infected. The difference in virulence is unrelated to changes in bacterial toxin production, bacterial growth, immune evasion, or cell surface properties. Instead, resistant strains were more vulnerable to a host proenzyme involved in the antibacterial melanization response, an important response deployed throughout the arthropods. We predict that daptomycin resistance forces staphylococci to alter the composition of their cell surface, which causes the bacteria to become more vulnerable to killing by melanization.
可获得抗菌抗性，这反过来可能会影响其致病潜力。我们使用一组在获得达托霉素抗性之前和之后收集的配对临床分离株，这些抗性大多通过单个突变获得，结果表明在全身感染模型中，达托霉素最低抑菌浓度的增加与毒力降低之间存在关联。通过分析毒素产生、细菌生长特性和细胞表面特性，我们未能将与达托霉素抗性相关的毒力减弱与毒力因子产生减少、适应性降低或所研究的任何细胞表面特性联系起来。在果蝇中的竞争试验也不支持免疫逃避能力有任何改变。相反，我们使用一组对各种免疫成分有缺陷的突变果蝇，结果表明这种与达托霉素抗性相关的毒力减弱主要是由于对前酚氧化酶（一种参与黑化作用的酪氨酸酶）的活性更敏感，而不是对抗菌肽或博马宁抗菌效应物敏感。进一步研究未能将与达托霉素抗性相关的毒力减弱与对活性氧或醌类的不同敏感性联系起来，而活性氧和醌类与酚氧化酶的细菌杀伤活性密切相关。综上所述，达托霉素抗性似乎通过基于复杂机制的对酚氧化酶的敏感性增强来减弱毒力。我们的研究为理解抗菌抗性、逃避免疫杀伤和毒力之间的相互作用提供了新的见解。重要性本研究通过探索抗菌抗性与毒力之间的相互作用，推进了宿主 - 微生物相互作用和抗菌抗性领域的现有知识。它展示了获得抗菌抗性如何改变细菌毒力并影响毒力形成。相对于亲本葡萄球菌菌株，耐达托霉素的临床分离株通常在参与细菌膜组成的一个基因中发生单个突变，并且当感染果蝇时这些菌株的毒力要低得多。毒力差异与细菌毒素产生、细菌生长、免疫逃避或细胞表面特性的变化无关。相反，抗性菌株更容易受到宿主中参与抗菌黑化反应的一种前酶的影响，黑化反应是节肢动物普遍存在的一种重要反应。我们预测达托霉素抗性迫使葡萄球菌改变其细胞表面组成，这使得细菌更容易受到黑化作用的杀伤。
