Activity of Antibiotics against Staphylococcus aureus in an In Vitro Model of Biofilms in the Context of Cystic Fibrosis: Influence of the Culture Medium
Activity of Antibiotics against Staphylococcus aureus in an In Vitro Model of Biofilms in the Context of Cystic Fibrosis: Influence of the Culture Medium
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DOI：
10.1128/aac.00602-19
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发表时间：
2019-07-01
影响因子：
4.9
通讯作者：
Van Bambeke, Francoise
中科院分区：
文献类型：
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作者：
Iglesias, Yvan Diaz;Wilms, Tobias;Van Bambeke, Francoise
金黄色葡萄球菌是囊性纤维化（CF）年轻患者呼吸道中的一种高度流行的病原体，可引起生物膜相关感染。在这里，我们建立了一个在胰蛋白酶大豆肉汤补充葡萄糖和NaCl（TGN）或人工痰液培养基（ASM）中生长的生物膜的体外模型，并使用它来评估在CF患者中使用的抗生素的活性和对葡萄球菌（美罗培南，万古霉素，阿奇霉素，利奈唑胺，利福平，环丙沙星，妥布霉素）的活性的药效学基础。流变学研究表明，ASM的弹性比粘性更大，CF患者的Alzheeta也观察到了这一点，弹性模量和粘性模量分别与CF Alzheta相似和略低。对甲氧西林敏感的S.金黄色葡萄球菌菌株ATCC 25923和耐甲氧西林的S.金黄色葡萄球菌菌株ATCC 33591在24小时后达到成熟，ASM中的生物量（通过结晶紫染色测量）和代谢活性（通过随后的刃天青代谢评估）低于TGN中，并且两种培养基中的活力（通过细菌计数评估）相似。培养生物膜24小时后获得的抗生素的完整浓度-响应曲线表明，所有抗生素在ASM中的活性、代谢活性和生物量都大大低于TGN。选择妥布霉素用于小菌落变体，特别是在ASM中生长的生物膜中;无法确定这些变体的营养缺陷型。这些数据突出了培养基对S.金黄色葡萄球菌对生物膜中抗生素的反应。ASM的使用可能有助于确定有效的药物浓度或评估针对CF患者生物膜的新治疗方案。
Staphylococcus aureus is a highly prevalent pathogen in the respiratory tract of young patients with cystic fibrosis (CF) and causes biofilm-related infections. Here, we set up an in vitro model of a biofilm grown in Trypticase soy broth supplemented with glucose and NaCl (TGN) or in artificial sputum medium (ASM) and used it to evaluate on a pharmacodynamic basis the activity of antibiotics used in CF patients and active on staphylococci (meropenem, vancomycin, azithromycin, linezolid, rifampin, ciprofloxacin, tobramycin). Rheological studies showed that ASM was more elastic than viscous, as was also observed for sputa from CF patients, with elastic and viscous moduli being, respectively, similar to and slightly lower than those of CF sputa. Biofilms formed by methicillin-sensitive S. aureus strain ATCC 25923 and methicillin-resistant S. aureus strain ATCC 33591 reached maturity after 24 h, with biomass (measured by crystal violet staining) and metabolic activity (assessed by following resazurin metabolization) being lower in ASM than in TGN and viability (assessed by bacterial counts) being similar in both media. Full concentration-response curves of antibiotics obtained after 24 h of incubation of biofilms showed that all antibiotics were drastically less potent and less efficient in ASM than in TGN toward viability, metabolic activity, and biomass. Tobramycin selected for small-colony variants, specifically in biofilms grown in ASM; the auxotrophism of these variants could not be established. These data highlight the major influence exerted by the culture medium on S. aureus responsiveness to antibiotics in biofilms. The use of ASM may help to determine effective drug concentrations or to evaluate new therapeutic options against biofilms in CF patients.